手性金属卤化物纳米结构中的圆偏振发光：从手性传递机制到自旋光电器件

… detection and generation of circularly polarized light. The use of chiral materials would thus … Fabrication of nanostructures to obtain chiral metamaterials has proven to be an effective …

Metal halide perovskites (MHPs) have emerged as highly appealing materials for circularly polarized luminescence (CPL) related applications, owing to their spin-related photoelectric properties and flexible structural adjustment.

Using ligand exchange on FAPbI3 perovskite nanocrystals (PNCs) surface with chiral tridentate l-cysteine (l-cys) ligand, we successfully prepared chiral FAPbI3 PNCs that show circularly polarized luminescence (CPL) (dissymmetry factor; glum = 2.1 × 10-3) in the near-infrared (NIR) region from 700 to 850 nm and a photoluminescence quantum yield (PLQY) of 81%. The chiral characteristics of FAPbI3 PNCs are ascribed to induction by chiral l/d-cys, and the high PLQY is attributed to the passivation of the PNCs defects with l-cys. Also, effective passivation of defects on the surface of FAPbI3 PNCs by l-cys results in excellent stability toward atmospheric water and oxygen. The conductivity of the l-cys treated FAPbI3 NC films is improved, which is attributed to the partial substitution of l-cys for the insulating long oleyl ligand. The CPL of the l-cys ligand treated FAPbI3 PNCs film retains a glum of -2.7 × 10-4. This study demonstrates a facile yet effective approach to generating chiral PNCs with CPL for NIR photonics applications.

Chiral nano‐emitters have recently received great research attention due to their technological applications and the need for a fundamental scientific understanding of the structure‐property nexus of these nanoscale materials. Lead halide perovskite nanocrystals (LHP NCs) with many interesting optical properties have anticipated great promise for generating chiral emission. However, inducing high anisotropy chiral emission from achiral perovskite NCs remains challenging. Although chiral ligands have been used to induce chirality, their anisotropy factors (glum) are low [10−3 to 10−2]. Herein, the generation of high anisotropy circularly polarized photoluminescence (CPL) from LHP NCs is demonstrated using chiral metasurfaces by depositing nanocrystals on top of prefabricated resonant photonic structures (2D gammadion arrays). This scalable approach results in CPL with glum to a record high of 0.56 for perovskite NCs. Furthermore, the differences between high‐index dielectric chiral metasurfaces and metallic ones are explored for inducing chiral emission. More importantly, the generation of simultaneous multi‐wavelength circularly polarized light is demonstrated by combining dielectric and metallic chiral metasurfaces.

Circularly polarized light is previously shown as a chiral bias to enable the synthesis of chiral plasmonic nanomaterials through light‐matter interactions. The traditional approach for circularly polarized light generation relies on a “top‐down” approach by removing undesired light polarization through optics, which suffers from energy loss and compatibility issues. An alternative approach is to develop chiral phosphors that emit efficient circularly polarized luminescence (CPL). However, most materials fail to produce processable CPL with both high quantum yield and dissymmetry factors, let alone the synthesis of chiral nanomaterials. Herein, a liquid‐crystal‐templated framework is developed to assemble halide perovskite nanocrystals, CsPbX3 (X = Cl, Br, I), and achieved efficient CPL with the record‐high figure of merit (FM) for three primary colors (Red, Green, Blue). The fidelity of the CPL is further demonstrated in the synthesis of chiral gold nanoparticles, where a five‐fold increase in optical activity is achieved.

The versatile hybrid perovskite nanocrystals (NCs) are one of the most promising materials for optoelectronics by virtue of their tunable bandgaps and high photoluminescence (PL) quantum yields. However, their inherent crystalline chemical structure limits the chiroptical properties achievable with the material. The production of chiral perovskites has become an active field of research for its promising applications in optics, chemistry, or biology. Typically, chiral halide perovskites are obtained by the incorporation of different chiral moieties in the material. Unfortunately, these chemically modified perovskites have demonstrated moderate values of chiral PL so far. Here, a general and scalable approach is introduced to produce chiral PL from arbitrary nanoemitters assembled into 2D‐chiral metasurfaces. The fabrication via nanoimprinting lithography employs elastomeric molds engraved with chiral motifs covering millimeter areas that are used to pattern two types of unmodified colloidal perovskite NC inks: green‐emissive CsPbBr3 and red‐emissive CsPbBr1I2. The perovskite 2D‐metasurfaces exhibit remarkable PL dissymmetry factors (glum) of 0.16 that can be further improved up to glum of 0.3 by adding a high‐refractive‐index coating on the metasurfaces. This scalable approach to produce chiral photoluminescent thin films paves the way for the seamless production of bright chiral light sources for upcoming optoelectronic applications.

Halide perovskite nanomaterials have emerged as a transformative platform for generating and manipulating polarized luminescence, offering unprecedented opportunities for next‐generation optoelectronic technologies. This review comprehensively examines recent advances in engineering both linearly polarized luminescence (LPL) and circularly polarized luminescence (CPL) from perovskite nanostructures, focusing on structural design principles, chirality transfer mechanisms, and performance optimization strategies. Methods are systematically analyzed to achieve polarized emission, including anisotropic nanocrystal growth, chiral ligand functionalization, and liquid crystal‐mediated alignment, while highlighting critical optical factors such as dissymmetry factors and photoluminescence quantum yield. Key challenges in enhancing the precision control over perovskite nanostructures, room‐temperature CPL efficiency, and scalable assembly are discussed, with a forward‐looking perspective on the integration of artificial intelligence (AI) to accelerate progress in the development of perovskite nanomaterials with customized polarized luminescence. By bridging fundamental insights with technological applications, this review outlines a roadmap for developing perovskite‐based polarized light sources that combine high performance, stability, and manufacturability, which are key enablers for the future of quantum photonics, ultra‐secure communication, and intelligent optical systems.

Chiral hybrid metal halides are rapidly emerging as a promising class of semiconductors for next‐generation circularly polarized (CP) optoelectronics. As low‐toxicity analogues to asymmetric lead‐based perovskites, these materials combine strong spin–orbit coupling with intrinsic or induced structural asymmetry, enabling robust chiroptical activity. Capable of generating circularly polarized photoluminescence and electroluminescence (EL), they offer exciting opportunities for applications in circularly polarized light‐emitting diodes (CP‐LED), CP‐sensitive photodetectors, and spin‐selective photovoltaics. In this review, we summarize recent progress in the design, synthesis, and device applications of lead‐free chiral metal halides, including Sn‐, Sb‐, Mn‐, Cu‐, Ln‐ and In/Sb‐based perovskites and related halide frameworks, by highlighting how crystallographic chirality, dimensionality, and chemical composition govern their electronic structure and CPL behavior. We discuss the structure–property relationship that underpins CP‐EL efficiency and dissymmetry factors, and reveal how optoelectronic devices accommodate these materials for spin‐polarized light emission and detection. Finally, we outline existing problems, key challenges and future directions toward scalable, high‐performance, and environmentally friendly CPL optoelectronic devices based on lead‐free chiral metal‐halide semiconductors.

Solution‐processable lead halide perovskites possess excellent optical and electronic properties as one of the best candidates for optoelectronics. Especially, some of the perovskites show high quantum efficiency in photoluminescence, which enables their promising application in next‐generation light‐emitting materials and devices. More interestingly, the highly crystalline nature of perovskites as well as the intrinsic spin selectivity of exciton transitions introduces fascinating polarization properties into the light emission from lead halide perovskites. Herein are summarized the recent advances in the studies of polarized photoluminescence from lead halide perovskites in terms of both in‐depth understanding and potential application. The bright excitons in perovskite materials provide spin sublevels that give rise to radiative transitions carrying angular momentum, which is essential for the observation of polarized light emission. The polarization in photoluminescence can be amplified or modulated by introducing functional units such as chiral ligands in the chemical components of perovskites. Incorporating highly ordered microstructures into the perovskite materials is proved to be an effective way to further enhance the polarization properties at the macroscopic scale. The chemical and structural versatility of lead halide perovskites allows utililization of their characteristics of optical polarization in the construction of light sources, photodetectors, display devices, and so on.

… , chiral luminescent materials, which involve either covalent or noncovalent interactions, provide a more direct means of generating circularly polarized luminescence (… nanoparticles, on …

Chiral inorganic nanostructures strongly interact with photons changing their polarization state. The resulting circularly polarized light emission (CPLE) has cross‐disciplinary importance for a variety of chemical/biological processes and is essential for development of chiral photonics. However, the polarization effects are often complex and their interpretation is dependent on the several structural parameters of the chiral nanostructure. CPLE in nanostructured media has multiple origins and several optical effects are typically convoluted into a single output. Analyzing CPLE data obtained for nanoclusters, nanoparticles, nanoassemblies, and nanocomposites from metals, chalcogenides, perovskite, and other nanostructures, it is shown here that there are several distinct groups of nanomaterials for which CPLE is dominated either by circularly polarized luminescence (CPL) or circularly polarized scattering (CPS); there are also many nanomaterials for which they are comparable. The following points are also demonstrated: 1) CPL and CPS contributions involve light−matter interactions at different structural levels; 2) contribution from CPS is especially strong for nanostructured microparticles, nanoassemblies, and composites; and 3) engineering of materials with strongly polarized light emission requires synergistic implementation of CPL and CPS effects. These findings are expected to guide development of CPLE materials in a variety of technological fields, including 3D displays, information storage, biosensors, optical spintronics, and biological probes.

Circularly polarized (CP) photodetection has become a cornerstone technology in advancing fields such as quantum communication, biomedical imaging, and secure optical encryption. Conventional CP photodetectors relying on external optical components face challenges in miniaturization and efficiency, driving the exploration of chiral-sensitive materials for direct polarization discrimination. Among these, chiral metal halides have emerged as a revolutionary platform due to their intrinsic spin-orbit coupling, structurally tailorable chirality, and solution processability, enabling unprecedented photocurrent dissymmetry factors and broad absorption wavelengths. This review comprehensively examines the fundamental principles, material innovations, and device engineering strategies underpinning chiral metal halide-based CP photodetectors. Furthermore, representative applications of chiral metal halide-based CP photodetectors exploiting their emergent properties in high-precision circular polarization imaging, dynamic information encryption and bionic neuromorphic perception are examined. Finally, persisting challenges and future research directions are outlined for chiral metal halide-based CP photodetectors.

Chiral organic ligand‐incorporated low‐dimensional metal‐halide perovskites have received increasing attention for next‐generation photodetectors because of the direct detection capability of circularly polarized light (CPL), which overcomes the requirement for subsidiary optical components in conventional CPL photodetectors. However, most chiral perovskites have been based on low‐dimensional structures that confine chiroptical responses to the ultraviolet (UV) or short‐wavelength visible region and limit photocurrent due to their wide bandgap and poor charge transport. Here, chiroptical properties of 3D Cs0.05FA0.5MA0.45Pb0.5Sn0.5I3 polycrystalline films are achieved by incorporating chiral plasmonic gold nanoparticles (AuNPs) into the mixed PbSn perovskite, without sacrificing its original optoelectronic properties. CPL detectors fabricated using chiral AuNP‐embedded perovskite films can operate without external power input; they exhibit remarkable chirality in the near‐infrared (NIR) region with a high anisotropy factor of responsivity (gres) of 0.55, via giant plasmon resonance shift of chiral plasmonic AuNPs. In addition, a CPL detector array fabricated on a plastic substrate demonstrates highly sensitive self‐powered NIR detection with superior flexibility and durability.

Hybrid organic-inorganic perovskites allow the synthesis of high-quality, nanostructured semiconducting films via easily accessible solution-based techniques. This has allowed tremendous development in optoelectronic applications, primarily solar cells and light-emitting diodes. Allowed by the ease of access to nanostructure, chirality has recently been introduced in semiconducting perovskites, as a promising way to obtain advanced control of charge and spin and for developing circularly polarized light sources. Circular polarization of photo-luminescence (CPL) is a powerful tool to probe the electronic structure of materials. However, CPL in chiral perovskites has been scarcely investigated, and a study in bulk thin films and at room temperature is still missing. In this work we fabricate bromine-based chiral perovskites by using a bulky chiral organic cation mixed with CsBr, resulting in Ruddlesden-Popper perovskite thin films. We measure CPL on these films at room temperature and, by using unpolarized photo-excitation, we record a degree of circular polarization of photo-luminescence in the order of 10-3 and provide a full spectral characterization of CPL. Our results show that chirality is imparted on the electronic structure of the semiconductor; we hypothesize that the excess in polarization of emitted light originates from the charge in the photo-generated Wannier exciton describing an orbit in a symmetry-broken environment. Furthermore, our experiments allow to directly measure the magnetic dipole moment of the optical transition, which we estimate to be ≥ 0.1 μB. Finally, we discuss the implications of our findings on the development of chiral semiconducting perovskites as sources of circularly polarized light.

Circularly polarized luminescence (CPL) represents a unique optical phenomenon where emitted light exhibits a specific circular polarization, offering significant advantages in advanced photonic applications. Luminescent nanoparticles capable of CPL have garnered increasing attention due to their potential in enhancing display technologies, bioimaging contrast, and quantum information processing. Despite rapid progress, challenges still remain in synthesizing nanoparticles with high CPL efficiency, good stability, and tunable optical properties. The interplay between nanoparticle size, morphology, and chiral surface functionalization critically influences their luminescence and chiroptical performance. This review comprehensively discusses recent advances in the preparation, performance, and applications of CPL-active nanoparticles. Key synthetic strategies including molecular self-assembly, chiral ligand functionalization, chiral environment induction, and hybrid organic-inorganic approaches are detailed, highlighting how they enable precise control over CPL properties. Critical performance metrics such as dissymmetry factor (glum), quantum yield, and circularly polarized luminescence brightness (B-CPL) are examined, alongside the influence of nanoparticle size, morphology, and environmental factors on CPL efficiency. The review also introduces emerging applications in optical displays, stimuli-responsive sensing, multilevel data encryption, and bioimaging, underscoring the role of CPL nanoparticles in developing next-generation photonic and optoelectronic devices. Finally, current challenges and future directions for enhancing CPL performance and practical applicability are discussed.

Circularly polarized luminescence (CPL) materials are currently an important class of chiroptical materials that are attracting increasing interest. Nanoassemblies constructed from chiral or achiral building blocks show great potential for achieving CPL-active nanomaterials with high quantum yields and dissymmetry factors, which is crucial for further applications. In nanoassemblies, the dimensional morphology affects the chiroptical properties significantly since the microscopic packing modes will affect the luminescence processes and chirality transfer processes. In this review, we will show some examples for illustrating the relationship between multi-dimensional morphology and chiroptical properties. Furthermore, with dimensional morphology tuning, higher dissymmetry factors would be obtained. We hope to provide a useful and powerful insight into the design and control of CPL-active nanoassemblies via morphology control.

Circularly polarized luminescence (CPL) from assembled nanoscale materials presents a rapidly advancing field with significant implications for optoelectronics, bioimaging, and chiral photonics. The ability to engineer CPL-active systems through the controlled assembly of nanoscale particles offers a versatile platform for tuning chiroptical properties beyond what is possible with individual components. This review provides a comprehensive overview of design strategies for achieving efficient CPL emission from nanoscale particles and their assemblies. We systematically differentiate between the design approach and the specific nanoscale entities employed, analyzing the benefits and limitations associated with each. A particular emphasis is placed on hierarchical chiral structures capable of exhibiting CPL activity, whether constructed from inherently chiral or achiral building blocks. For assemblies composed of achiral components, we delve into the physicochemical mechanisms underlying their emergent chirality and CPL behavior. In the final part of the review, we highlight recent advances and future prospects in the field, with a focus on the development of stable, high-performance CPL-active nanomaterials for applications in optoelectronics, bioimaging, and chiral photonics.

Organic–inorganic hybrid halide perovskites (OIHPs) are commonly used as prototypical materials for various applications, including photovoltaics, photodetectors, and light‐emitting devices. Since the chiroptical properties of OIHPs are deciphered in 2017, chiral OIHPs have been rediscovered as new hybrid systems comprising chiral organic molecules and achiral inorganic octahedral layers. Owing to their exceptional optoelectrical properties and structural flexibility, chiral OIHPs have received a considerable amount of attention in chiral photonics, chiroptoelectronics, spintronics, and ferroelectrics. Despite their intriguing chiral properties, the transfer mechanism from chiral molecules to achiral semiconductors has not been extensively investigated. Furthermore, an in‐depth understanding of the origin of chiroptical activity is still elusive. In this review article, recent advances in the chiroptical activities of chiral OIHPs and polarization‐based devices adopting chiral OIHPs are comprehensively discussed, and insight into the underlying chirality transfer mechanism based on theoretical considerations is provided. This comprehensive survey, with an emphasis on the chirality transfer mechanism, will help readers understand the chiroptical properties of OIHPs, which are crucial for the development of spin‐based photonic and optoelectronic devices. Additionally, promising strategies to exploit the potential of chiral OIHPs are also discussed.

… Through such cogelation, the molecular chirality can transfer to the NCs resulting in CPL signals … induced chirality of perovskite NCs in chiral gels. Chiral lipid could form gel with chiral …

Hybrid perovskite semiconductor materials are predicted to lock chirality into place and encode asymmetry into their electronic states, while softness of their crystal lattice accommodates lattice strain to maintain high crystal quality with low defect densities, necessary for high luminescence yields. We report photoluminescence quantum efficiencies as high as 39% and degrees of circularly polarized photoluminescence of up to 52%, at room temperature, in the chiral layered hybrid lead-halide perovskites (R/S/Rac)-3BrMBA2PbI4 [3BrMBA = 1-(3-bromphenyl)-ethylamine]. Using transient chiroptical spectroscopy, we explain the excellent photoluminescence yields from suppression of nonradiative loss channels and high rates of radiative recombination. We further find that photoexcitations show polarization lifetimes that exceed the time scales of radiative decays, which rationalize the high degrees of polarized luminescence. Our findings pave the way toward high-performance solution-processed photonic systems for chiroptical applications and chiral-spintronic logic at room temperature.

Chiral perovskite nanocrystals have emerged as an interesting chiral excitonic platform that combines both structural flexibility and superior optoelectronic properties. Despite several recent demonstrations of optical activity in various chiral perovskite nanocrystals, efficient circularly polarized luminescence (CPL) with tunable energies remains a challenge. The chirality imprinting mechanism as a function of perovskite nanocrystal dimensionality remains elusive. Here, atomically thin inorganic perovskite nanoplatelets (NPLs) are synthesized with precise control of layer thickness and are functionalized by chiral surface ligands, serving as a unique platform to probe the chirality transfer mechanism at the organic/perovskite interface. It is found that chirality is successfully imprinted into mono‐, bi‐, and tri‐layer inorganic perovskite NPLs, exhibiting tunable circular dichroism (CD) and CPL responses. However, chirality transfer decreases in thicker NPLs, resulting in decreased CD and CPL dissymmetry factors for thicker NPLs. Aided by large‐scale first‐principles calculations, it is proposed that chirality transfer is mainly mediated through a surface distortion rather than a hybridization of electronic states, giving rise to symmetry breaking in the perovskite lattice and spin‐split conduction bands. The findings described here provide an in‐depth understanding of chirality transfer and design principles for distorted‐surface perovskites for chiral photonic applications.

Chiral ligand modification has emerged as a promising route to confer intrinsic chirality in perovskite nanocrystals (NCs), thereby imparting them with optically active properties and rendering great superiority in the next generation of circularly polarized luminescence. However, the functionalization of chiral ligand is not fully explored and the underlying mechanism governing chirality transfer remains elusive. Herein, tryptophan (Try), a naturally occurring chiral amino acid, is verified to serve as multidentate chiral ligands attaching on the surface of perovskite NCs. Such strong coordination favors the chirality imprinting on the electronic state of CsPbBr3, resulting in notable circular dichroism features and circularly polarized luminescence with a maximum glum of 2.3 × 10−3. It is intriguing that the intermolecular interaction between Try ligands anchored on two neighboring NCs contribute to chiral optical properties as well. The RDG‐NCI analysis have confirmed the hydrogen bond between the amine and carboxylic groups on chiral Try, which may drive the chiral assembly of perovskite NCs.

This work reports the synthesis of chiral perovskite heterostructure films by combining a two-dimensional (2D) chiral (R-/S-MBA)2PbI4 perovskite with CsPbBr3 quantum dots (QDs). The as-synthesized chiral heterostructure films exhibit obvious circularly polarized luminescence (CPL) properties, even though pure 2D chiral perovskite cannot present photoluminescence. It indicates that the chirality of the excited state of the QDs originates from the 2D chiral perovskite. The circular polarization-resolved transient absorption (TA) spectra further demonstrate that the CPL response of heterostructure films originates from the energy transfer between the chiral perovskite layer and QDs layer and the suppression of spin relaxation, which induces the imbalance of the spin population of excited states in QDs layer. In addition, the photoluminescence (PL), circular dichroism (CD), and CPL spectra of these heterostructure films can be controlled by varying the thickness and component of the chiral perovskite layer, which demonstrates that the anion exchange between chiral perovskite and CsPbBr3 QDs can tune the chemical composition and optoelectronic properties due to the low bonding energy difference between them and decrease the strain within the QDs layer to reduce the radiative recombination lifetime. This work provides guidance for the synthesis of chiral perovskites with a strong CPL response and further provides insight into the origination of CPL.

Halide perovskites have risen as promising circularly polarized luminescent (CPL) materials for applications in 3D displays, optical anti‐counterfeiting, and information storage. And yet, achieving highly anisotropic CPL emission from achiral halide perovskites remains fraught with challenges. Herein, the helical channels of chiral MOFs (L/D‐MOFs) are utilized as chiral templates for the in‐situ growth of CsPbBr3 perovskite nanocrystals (NCs), generating CPL‐active CsPbBr3@L/D‐MOFs materials with high luminescence dissymmetry factors (|glum|, 8.39×10−3) and high photoluminescence quantum yields (QY, 78%). Synchrotron‐radiation‐based X‐ray absorption spectroscopy clearly verifies that the embedded CsPbBr3 NCs inherit the helicity of L/D‐MOFs through strong Cd─Br coordination bonds, thereby facilitating chirality transfer from L/D‐MOFs to CsPbBr3 NCs. Additionally, the efficient Förster resonance energy transfer (FRET) from chiral L/D‐MOFs to CsPbBr3 NCs further amplifies the CPL signal of CsPbBr3 NCs. Benefiting from the excellent CPL properties and tunable emission, the CsPbX3@L/D‐MOFs demonstrate great potential in CPL‐LEDs. This work proposes a viable strategy for the rational design of high‐performance CPL‐active perovskite materials and offers profound insights into the chirality transfer mechanism.

Magnetic impurity doping in semiconductors has emerged as an important strategy to endow exotic photophysical and magnetic properties. While most reported hosts are centrosymmetric semiconductors, doping magnetic ions into a noncentrosymmetric chiral semiconductor can offer additional control of photonic and spin polarization. In this work, we synthesized a Mn2+-doped chiral two-dimensional (2D) perovskite, Mn2+:(R-MPA)2PbBr4 (R-MPA+ = R-methyl phenethylammonium). We found that the optical activity of chiral 2D perovskites is enhanced with an increased concentration of Mn2+ ions. Additionally, efficient energy transfer from the chiral host to the Mn2+ dopants is observed. This energy transfer process gives rise to circularly polarized luminescence from the excited state of Mn2+ (4T1 → 6A1), exhibiting a photoluminescence quantum yield up to 24% and a dissymmetry factor of 11%. The exciton fine structures of undoped and Mn2+-doped (R-MPA)2PbBr4 are further studied through magnetic circular dichroism (MCD) spectroscopy. Our analysis shows that chiral organic cations lead to an exciton fine structure splitting energy as large as 5.0 meV, and the splitting is further increased upon Mn2+ doping. Our results reveal the strong impacts of molecular chirality and magnetic dopants on the exciton structures of halide perovskites.

Chiral halide perovskites have emerged as promising materials for spin‐optoelectronic devices owing to their ability to emit circularly polarized light (CPL) through spin‐selective processes. However, the realization of high dissymmetry factors in perovskite‐based circularly polarized light‐emitting diodes (CP‐LEDs) remains challenging. Herein, CP‐LEDs based on quasi‐2D perovskites incorporating two types of chiral materials are demonstrated, which achieve high circular polarization. R‐/S‐methylbenzylammonium iodide (MBAI) is employed to construct quasi‐2D perovskite structures and R‐/S‐1,1′‐binaphthyl‐2,2′‐diyl hydrogen phosphate (BHP) to enhance chiral distortion. Enhanced CPL emission with higher dissymmetry factors is observed due to a synergistic effect of the matching handedness of MBAI and BHP. The enhanced circular dichroism in the absorption band of the n = 1 2D perovskite reveals the presence of chiral distortion, which leads to strong CPL emission. The results of density functional theory calculations and micro‐strain analysis are further supported by the observed chiral distortion of the inorganic perovskite lattice. Moreover, BHP effectively passivated the perovskite defects through its phosphate groups. The resulting CP‐LEDs exhibit an enhanced electroluminescence dissymmetry factor of 7.5 × 10−2 and an external quantum efficiency of 6.9%, demonstrating their potential for practical application in chiro‐optoelectronics.

Chiral lead halide perovskite nanocrystals (NCs) coherently integrate promising optical property with chirality, exhibiting great potential for next generation technologies across optoelectronics, asymmetric catalysis, chiral recognition, and 3D display technologies. However, the persistent challenges of weak optical activity and limited modulation methods in this material system severely hinder its practical implementation. Herein, a simple post‐treatment strategy is proposed for synthesizing chiral lead halide perovskite NCs with chiral amine ligands R/S‐3MPEA to modulate their optical properties and chiral characteristics. Experimental results demonstrate that the CsPbBr3 NCs treated with chiral amine ligands R/S‐3MPEA display mirror‐symmetric circular dichroism (CD) signals at 495 nm for R/S‐3MPEA‐modified NCs, with luminescence asymmetry factor glum reaching 0.64 × 10−3, unambiguously confirming their chiral nature. Furthermore, these NCs achieve exceptional optical performance in the visible spectrum, characterized by extended fluorescence lifetimes as a result of passivation. Additionally, the fabrication of light‐emitting diodes (LEDs) based on the chiral CsPbBr3 NCs with a chromaticity coordinate of (0.1097, 0.7430) at 80 mA validates the practical application. This research provides additional experimental evidence for the synthesis of chiral perovskite NCs and establishes a foundation for their applications in optoelectronics, spintronics, and related fields.

Chiral materials are of particular interest and have a wide range of potential applications in life science, material science, spintronic, and optoelectronic devices. Two-dimensional (2D) hybrid organic-inorganic lead halide perovskites have attracted increasing attention. Incorporating the chiral organic ligands into the layered lead iodide frameworks would introduce strong chirality in pure 2D perovskites for potential applications in circularly polarized light (CPL) emission and detection; nonetheless, studies on those aspects are still in their infancy. Here, we report on the strong CPL emission and sensitive CPL detection in the visible-wavelength range in pure chiral ( R-/ S-MBA)2PbI4 (MBA = C6H5C2H4NH3) 2D perovskites, which are successfully synthesized with a needle shape and millimeter size by incorporating the chiral molecules. The chiral 2D perovskites ( R-MBA)2PbI4 and ( S-MBA)2PbI4 exhibit an average degree of circularly polarized photoluminescence (PL) of 9.6% and 10.1% at 77 K, respectively, and a maximum degree of the circularly polarized PL of 17.6% is achieved in ( S-MBA)2PbI4. The degree of circularly polarized PL dramatically decreases with increasing temperature, implying that the lattice distortion induced by the incorporated chiral molecules and/or temperature-dependent spin flipping might be the origin for the observed chirality. Finally, CPL detection has been achieved with decent performance in our chiral 2D perovskite microplate/MoS2 heterostructural devices. The high degree of the circularly polarized PL and excellent CPL detection together with the layered nature of pure chiral 2D perovskites enables them to be a class of very promising materials for developing and exploring spin associated electronic devices based on the chiral 2D perovskites.

Introducing the chiral spacers to two-dimensional (2D) lead halide perovskites (LHPs) enables them to exhibit circularly polarized photoluminescence (CPPL), which could have applications in chiral-optics and spintronics. Despite that a great deal of effort has been made in this field, the reported polarization degree of CPPL at ambient conditions is still very limited, and the integration of multiple functionalities also remains to be explored. Here we report the structures, CPPL, and piezoelectric energy harvesting properties of chiral 2D LHPs, [R-1-(4-bromophenyl)ethylaminium]2PbI4 (R-[BPEA]2PbI4) and [S-1-(4-bromophenyl)ethylaminium]2PbI4 (S-[BPEA]2PbI4). Our results show that these chiral perovskites are direct bandgap semiconductors and exhibit CPPL centered at ∼513 nm with a maximum degree of polarization of up to 11.0% at room temperature. In addition, the unique configurational arrangement of the chiral spacers is found to be able to reduce the interlayer π-π interactions and consequently result in strong electron-phonon coupling. Furthermore, the intrinsic chirality of both R-[BPEA]2PbI4 and S-[BPEA]2PbI4 enables them to be piezoelectric active, and their composite films can be applied to generate voltages and currents up to ∼0.6 V and ∼1.5 μA under periodic impacting with a strength of 2 N, respectively. This work not only reports a high degree of CPPL but also demonstrates piezoelectric energy harvesting behavior for realizing multifunctionalities in chiral 2D LHPs.

… perovskite quantum dots reported by Zheng and Zeng [41, 42], we propose to load UCNP inside chiral CsPbX3 perovskite … the chiral PKNC, due to a through-space chirality transfer. The …

Chiral metal halide perovskites hold great potential as circularly polarized luminescent (CPL) materials owing to their exceptional optoelectronic properties. However, chirality-induced lattice distortions in intrinsically chiral systems often reduce photoluminescence (PL) efficiency, making it challenging to balance chirality and emission performance. In this study, we present a general strategy enabling efficient energy transfer (ET) from chiral quasi-two-dimensional (quasi-2D) perovskite nanosheets to achiral perovskite nanocrystals or dye molecules, achieving extended fluorescence lifetimes and enhanced CPL activity in achiral hosts. We establish a direct correlation between ET efficiency and chiral amplification in quasi-2D chiral perovskite/achiral perovskite composites. The Janus-type heterostructures exhibit remarkable ET efficiency and pronounced chiral amplification, leading to a fourfold increase in the photoluminescence quantum yield of achiral components and a luminescence dissymmetry factor (glum) value of 4.32 × 10-3, representing a 50% enhancement compared to pristine chiral perovskites. This design can be extended to achieve full-spectrum, white-light CPL emission. The optimized Janus composites show excellent environmental stability, highlighting their practical applicability. Overall, this work establishes a versatile platform for developing high-efficiency, spectrally tunable, and integrated CPL light sources, providing new opportunities for advanced chiroptoelectronic applications.

Upconverted circularly polarized luminescence (UCPL) processes have attracted great interest, because the chiroptical properties could be expressed in different photophysical processes. In this Letter, the first example of two-photon absorption-based upconverted circularly polarized luminescence (TP-UCPL) is demonstrated. The chiral α-octylamine-modified cesium lead bromides perovskite nanocrystals exhibited TP-UCPL with a two-photon absorption cross section at 800 nm (σ2,800 nm) up to 3.68 × 104 GM and luminescence dissymmetric factor ( glum) up to 7.0 × 10-3. Depending on the molecular chirality of the capping ligands, the TP-UCPL sense can be selected and the mirror-imaged CPL is obtained. It is envisaged that this approach will afford a new viewpoint for designing UCPL processes.

Chiral perovskite materials have intrigued enormous interests because of their appealing chiroptical properties and tailorable non‐centrosymmetric structures. However, it remains challenging to realize high‐efficiency blue emissive circularly polarized luminescence (CPL) of intrinsic chiral perovskite nanomaterials at room temperature. Herein, a robust and versatile electrospinning strategy is reported for in situ construction of chiral 2D and quasi‐2D perovskite nanosheets (PNSs) protected in polymer hybrid nanofibers. It is found that quasi‐2D chiral PNS/polymer possesses inherent chirality and enhanced CPL properties at room temperature compared to 2D counterparts. Notably, CPL emission color of chiral quasi‐2D PNS/polymer can be tuned from deep blue to sky blue, and a high luminescence dissymmetry values up to −8.0 × 10−3 can be achieved. Different perovskites, polymers, and nanofibrous structures are expanded to explore the universality of polymer protected PNSs. Significantly, compared to spin‐coated film, the stabilities of quasi‐2D PNS/polymer film are greatly improved due to the effective protection of polymer. The obtained PNS/polymer hybrid nanofiber films can be conveniently implemented for circularly polarized light emitting diode devices. This study may open up a new avenue for the scalable fabrication of chiral perovskite nanomaterials of interest and their applications in the CPL related fields.

Circularly polarized light (CPL) detection is required in various fields such as drug screening, security surveillance and quantum optics. Conventionally, CPL photodetector needs the installation of optical elements, imposing difficulties for integrated and flexible devices. The established CPL detectors without optical elements rely on chiral organic semiconductor and metal metamaterials, but they suffer from extremely low responsivity. Organic-inorganic hybrid materials combine CPL-sensitive absorption induced by chiral organics and efficient charge transport of inorganic frameworks, providing an option for direct CPL detection. Here we report the CPL detector using chiral organic-inorganic hybrid perovskites, and obtain a device with responsivity of 797 mA W-1, detectivity of 7.1 × 1011 Jones, 3-dB frequency of 150 Hz and one-month stability, a competitive combined feature for circularly polarized light detection. Thanks to the solution processing, we further demonstrate flexible devices on polyethylene terephthalate substrate with comparable performance. Optics-free circularly-polarized light detection has suffered from extremely low responsivity. Here Chen et al. demonstrate chiral organic–inorganic hybrid perovskite based detectors to distinguish circularly-polarized light with high responsivity of 797 mA/W.

The emergence of chiral metal halides marks a pivotal advancement in materials science, where structural asymmetry enables unprecedented control over spin-selective transport and polarized light interactions for optoelectronic and spintronic technologies. The introduction of chiral ligands into the metal halide lattice or on the surface of NCs imparts chirality to the corresponding hybrid materials, which adapts the handedness (R or S) of the chiral molecule. The choice of chiral molecule and metal halide type critically influences the crystal structure and dimensionality of metal halide crystals and thus their properties. Despite significant progress, the relationship between structure and chiroptical efficiency remains unclear. Nonetheless, they show great promise for spin filtering, enabling the fabrication of chiral LEDs and photodetectors. Considering these advancements, this Perspective focuses on the chiral-ligand-assisted design, synthesis, and functional exploration of chiral metal halide bulk and nanocrystals, along with the outstanding challenges that need to be addressed in the future.

Colloidal metal halide\nperovskite nanocrystals (NCs) with chiral\nligands are outstanding candidates as a circularly polarized luminescence\n(CPL) light source due to many advantages such as high photoluminescence\nquantum efficiency, large spin–orbit coupling, and extensive\ntunability via composition and choice of organic\nligands. However, achieving pronounced and controllable polarized\nlight emission remains challenging. Here, we develop strategies to\nachieve high CPL responses from colloidal formamidinium lead bromide\n(FAPbBr3) NCs at room temperature using chiral surface\nligands. First, we show that replacing a portion of typical ligands\n(oleylamine) with short chiral ligands ((R)-2-octylamine)\nduring FAPbBr3 NC synthesis results in small and monodisperse\nNCs that yield high CPL with average luminescence dissymmetry g-factor, glum = 6.8 ×\n10–2. To the best of our knowledge, this is the\nhighest among reported perovskite materials at room temperature to\ndate and represents around 10-fold improvement over the previously\nreported colloidal CsPbClxBryI3‑x‑y NCs. In order to incorporate\nNCs into any optoelectronic or spintronic application, the NCs necessitate\npurification, which removes a substantial amount of the chiral ligands\nand extinguishes the CPL signals. To circumvent this issue, we also\ndeveloped a postsynthetic ligand treatment using a different chiral\nligand, (R-/S-)­methylbenzylammonium\nbromide, which also induces a CPL with an average glum = ±1.18 × 10–2. This postsynthetic\nmethod is also amenable for long-range charge transport since methylbenzylammonium\nis quite compact in relation to other surface ligands. Our demonstrations\nof high CPL and glum from both as-synthesized\nand purified perovskite NCs at room temperature suggest a route to\ndemonstrate colloidal NC-based spintronics.

Summary Chiral halide perovskites have recently emerged as a class of potential optoelectronic materials. In this review, we mainly aim to provide a comprehensive understanding of chiral halide perovskite crystals for optoelectronic applications. An overview of the research background and advancement of chiral halide perovskites is described. Crystal structure, synthesis, and growth methods of chiral halide perovskite single crystals are demonstrated. Moreover, the characteristic properties and optoelectronic applications of chiral halide perovskites are systematically illustrated. Finally, future research opportunities and challenges of chiral halide perovskite single crystals and related devices are provided, concluding with our perspective on the burgeoning optoelectronic field.

Chiral materials with intrinsic inversion‐symmetric structures possess many unique physicochemical features, including circular dichroism, circularly polarized photoluminescence, nonlinear optics, ferroelectricity, and spintronics. Halide perovskites have attracted considerable attention owing to their excellent optical and electrical properties, which are particularly suitable for realizing high power‐conversion efficiency in solar cells. Recent studies have shown that chirality can be transferred from chiral organic ligands into halide perovskites and the resultant chiral perovskites combine the advantages of both chiral materials and halide perovskites; this provides an ideal platform to design next‐generation optoelectronic and spintronic devices. In this progress report, the most recent advances are summarized in various chemical structures of chiral perovskites, their synthesis strategies, chirality generation mechanisms, and physical properties. Furthermore, the potential chiral‐halide‐perovskite‐based applications are presented and the challenges and prospects of chiral perovskites are discussed. This report outlines the diverse construction strategies of and proposes research directions for chiral halide perovskites; thus, it provides insights into the design of novel chiral perovskites and facilitates investigation of the optoelectronic applications that employ chirality.

Self‐assembly of lead halide perovskite nanocrystals (NCs) into close‐packed, long‐range‐ordered nanostructures can effectively modulate their photoelectronic properties, yet significantly challenging. Herein, an efficient approach is reported to induce the hierarchical self‐assembly of perovskite CsPbBr3 NCs by phase transition using chiral cysteine ligands, yielding asymmetric Cs4PbBr6 nanorods (NRs) with the circularly polarized luminescent response. An interfacial phase transition process is found during the conversion of CsPbBr3 nanocubes to Cs4PbBr6 NCs initiated by cysteine molecules. Then the Cs4PbBr6 NCs aggregate sequentially to form nanoclusters, which further self‐assemble into the chiral Cs4PbBr6 NRs. Molecular dynamics simulations reveal that the Cs4PbBr6 nanochains gradually approach each other to achieve an asymmetric structure, and the simulated circular dichroism spectrum further supports the formation of a chiral structure. This work offers a facile method for the hierarchical chiral self‐assembly of lead halide perovskite nanostructures, which brings new insights to explore chiral nanostructures by modulating the surface chemistry and post self‐assembly.

… Here we report a general approach to grow single-crystalline 3D lead halide perovskites … We thank YK Wang and QQ He for their help in perovskite nanocrystal synthesis; P. Wang for …

Chiral\nnanomaterials have drawn extensive attention on account\nof numerous application prospects in optoelectronics, asymmetric catalysis,\nchiral recognition, and three-dimensional (3D) display. Thereinto,\nchiral perovskite has been a hotspot due to brilliant optoelectronic\nproperties, but some problems limit the development, including low\nquantum yield, low chiral intensity, and the lack of facile regulation.\nTo overcome these issues, an effective ligand exchange strategy, i.e. the interface modification has been proposed for chiral\nperovskite nanocrystals (PNCs). With the surface modification of CsPbBr3 PNCs with chiral organic ammonium in methyl acetate in the\ntypical purification process, excellent circular dichroism (CD) signals\nwere obtained and defects were eliminated, leading to an increase\nin the photoluminescence quantum yield (PLQY) from 50% to nearly 100%.\nThe CD signal can be regulated through a ligand exchange strategy\nin the longitudinal dimension, the chiral intensity, and the transverse\ndimension, the wavelength range. Here, the proper addition of R-α-PEAI\ninto the R-α-PEABr-capped CsPbBr3 PNCs can produce\na superstrong CD signal with the highest anisotropy factor (g-factor) of 0.0026 in the visible region among reported\nchiral colloidal PNCs. Simultaneously, the luminescence emission can\nbe tuned from the green to red region with boosted PLQY through the\napproach. The density functional theory (DFT) calculation result supports\nthat chirality comes from the hybridization between the energy level\nof a perovskite structure and that of chiral organic molecules. These\nproperties can be used in the structural engineering of high-performance\nchiral optical materials, spin-polarized light-emitting devices, and\npolarized optoelectronic devices.

Chirality is a ubiquitous feature in biological systems and occurs even in certain inorganic crystals. Interestingly, some inorganic nanocrystals have been shown to possess chirality, despite their achiral bulk forms. However, the mechanism of chirality formation and chiroptical responses in such nanocrystals is still ambiguous due to the presence of chiral organic ligands used to passivate such nanocrystals. Here, we recognize intrinsic chiroptical responses from lead halide perovskite nanowires with different length scales. Cube-connected nanowires with minimum interfacial contacts make their arrangement chiral for chiroptical responses even in the absence of chiral ligands. The chiral nanowires with varying lengths serve as a systematic platform for improving dissymmetric factors significantly with increasing lengths. The dissymmetric factor of the longest nanowires reaches 1.4 × 10-2, which is the highest among the intrinsic chiral perovskite nanocrystals at present. The nanowires generate circularly polarized luminescence, which has been seldom reported in halide perovskite nanocrystals in the absence of any chiral ligands. Furthermore, we find that chirality exists in the basic unit consisting of two corner-connected cubes in the form of a dimer. The intrinsic chirality of the nanowires is determined by the lattice rotation of connected cubes along the interfacial boundaries, which is different from the commonly observed chirality induced by chiral ligands. Such chiral lead halide perovskite nanocrystals with robust chiroptical properties provide an ideal platform for understanding the origin of intrinsic chirality and the rational design of anisotropic chiral nanostructures.

Circularly polarized luminescence (CPL) of chiral perovskite nanocrystals is crucial for applications such as spin-polarized light-emitting diodes and chiral photodetectors. However, the reported luminescence dissymmetry factors are often too low for practical applications; it is also important for CPL wavelengths to cover the red emission range for display applications. Herein, we realized helical perovskite nanowires self-assembled from red-emitting CsPbI3 quantum dots (QDs) with a strong CPL signal around 640 nm, which was enabled by chiral ligand R-/S-binaphthyl phosphoric acid. The formation of CsPbI3 nanowires from perovskite QDs occurred by oriented attachment; QDs remaining in solution attached at the surface of the nanowires, forming helical structures. The films produced from these chiral nanowires demonstrate high dissymmetry factors of 1.1 × 10-2 and 2.3 × 10-2 for absorption and luminescence, respectively, surpassing many previously reported chiral nanomaterials. We employed multilayer nanowire films as chiral filters, generating left- and right-handed CPL.

We have synthesized inherently chiral cesium lead halide perovskite magic-sized clusters (PMSCs) and ligand-assisted metal halide molecular clusters (MHMCs) using the achiral ligands octanoic acid (OCA) and octylamine (OCAm). UV–vis electronic absorption was used to confirm characteristic absorption bands while circular dichroism (CD) spectroscopy was utilized to determine their chiroptical activity in the 412–419 and 395–405 nm regions, respectively. In contrast, the larger sized counterpart of PMSCs, namely, perovskite quantum dots (PQDs), do not show chirality. The inherent chirality of the clusters is tentatively attributed to a twisted chiral layered structure, defect-induced chiral structure, or twisted Pb–Br octahedra.

… in chiral metal–halide perovskites, focusing on their synthesis … To understand the essence of chirality in halide perovskites … chiral ligands have long been used to modify perovskite …

Chiral perovskite nanocrystals (PeNCs) scintillators hold great potential for reducing optical crosstalk in X-ray imaging, due to their circularly polarized radioluminescence (CPRL) properties. However, due to the weak binding of chiral ligands and inefficient chirality transfer, achieving chiral PeNCs with high radioluminescence dissymmetry factors (gRL) remains a challenge. Here, we introduce polydimethylsiloxane (PDMS) as a CPRL-enhancing modifier that anchors chiral ligands to PeNCs surfaces through σ-π interactions. As a result, these chiral PeNCs exhibit a high gRL of 3.13 × 10-2, together with a near-unity photoluminescence quantum yield and a large asymmetry factor (glum) of 3.10 × 10-2, representing the highest chiral optical performance reported for chiral scintillators. We then, for the first time, demonstrate that these high-performance chiral PeNCs film can effectively suppress optical crosstalk to enhance X-ray imaging quality, opening a new avenue for designing advanced chiral PeNCs with significantly broadened practical applicability.

Chiroptical properties are of interest for various applications, including structure determination, polarized photodetectors, and spintronics. Inducing chiroptical activity into semiconductors is challenging because of difficulties in creating asymmetric crystal structures. One promising method is to use chirality transfer by deploying chiral organic molecules as capping ligands for nanocrystals. Experimentally, chiral-capped nanocrystals show emergent chiroptical signatures, but the mechanisms for chirality transfer remain unclear. Here we utilize atomistic modeling using time-dependent density functional theory calculations to explore chirality transfer in CsPbX3 (X = Cl, I) clusters capped with chiral diaminocyclohexane (DACH) enantiomers. When DACH enantiomers are bound to the cluster surface, the perovskite optical transitions gain chiral signatures. This observed chirality transfer is best rationalized by chiral molecular dipole-cluster transition dipole coupling. With multiple DACH molecules bound to the cluster surface, anisotropy factors are found to increase proportionally to the surface ligand density, providing mechanistic insight toward improving chiroptical functionality in semiconductor nanomaterials.

… chiral nanoantenna array that was coated with a monolayer of cubic all-inorganic lead halide perovskite nanocrystals… The cesium lead bromide perovskite NCs were synthesized via an …

Introducing molecular chirality into perovskite crystal structures has enabled the control of carrier spin states, giving rise to circularly polarized luminescence (CPL) in thin films and circularly polarized electroluminescence (CPEL) in LEDs. Spin-LEDs can be fabricated either through a spin-filtering layer enabled by chiral-induced spin selectivity or a chiral emissive layer. The former requires a high degree of spin polarization and a compatible spinterface for efficient spin injection, which might not be easily integrated into LEDs. Alternatively, a chiral emissive layer can also generate circularly polarized electroluminescence, but the efficiency remains low and the fundamental mechanism is elusive. In this work, we report an efficient green LED based on quasi-two-dimensional (quasi-2D) chiral perovskites as the emitting layer (EML), where CPEL is directly produced without separate carrier spin injection. The optimized chiral perovskite thin films exhibited strong CPL at 535 nm with a photoluminescence quantum yield (PLQY) of 91% and a photoluminescence dissymmetry factor (glum) of 8.6 × 10-2. Efficient green spin-LEDs were successfully demonstrated, with a large EL dissymmetry factor (gEL) of 7.8 × 10-2 and a maximum external quantum efficiency (EQE) of 13.5% at room temperature. Ultrafast transient absorption (TA) spectroscopic study shows that the CPEL is generated from a rapid energy transfer accompanied by spin transfer from 2D to 3D perovskites. Our study not only demonstrates a reliable approach to achieve high performance spin-LEDs but also reveals the fundamental mechanism of CPEL with an emissive layer of chiral perovskites.

… NCs, known for their high photoluminescence quantum yield (PLQY), superior solution … as that used above for calculating g lum to determine g CP-EL . The highest g CP-EL values are …

Organic–inorganic metal halides (OIMHs) have emerged as highly promising semiconductor materials owing to their outstanding optoelectronic properties. Incorporation of chiral organic molecules into the metal–halide framework enables the construction of chiral OIMHs, which exhibit unique chiroptical phenomena in addition to the intrinsic advantages of perovskite-based semiconductors. This review provides a systematic overview of recent progress in chiral OIMHs, covering synthetic approaches, crystal structures, mechanisms of chirality transfer, circularly polarized luminescence, and circularly polarized light detection. We further highlight the current challenges and outline future research directions, emphasizing the need for strategies that enhance chiroptical responses, stability, and device integration. By bridging fundamental insights with design principles, this work aims to guide the rational development of next-generation chiral functional materials for advanced optoelectronic and spintronic applications.

… chirality transfer, emission modulation, device efficiency, and operational stability remains insufficiently developed. To advance the application of chiral perovskite … high glum and PLQY …

Chiral microlasers hold great promise for optoelectronics from integrated photonic devices to high-density quantum information processing. Despite significant progress in lead-halide perovskite emitters, chiral lasing with high dissymmetry factors (glum) has not yet been realized. Here, we demonstrate chiral single-mode microlasers with exceptional stability and tunable emission across the visible range by combining CsPbClxBr3-x perovskite microrods (MRs) with a cholesteric liquid crystal (CLC) layer. The MRs lase via a whispering gallery mode (WGM) microcavity and confer chirality through the encapsulated CLC layer, thus exhibiting circularly polarized lasing with dissymmetry factors reaching 1.62. Importantly, we demonstrate wavelength-tunable high dissymmetry chiral lasers in a broad spectral range by tuning the halide composition and using CLC layers with the desired photonic bandgap (PBG). This facile approach to generate chiral lasing not only is applicable to semiconductor nano- and microcrystals but also paves the way for potential integration into nanoscale photonic devices.

Chiral quantum emitters attract significant interest for their unique non-reciprocal photon-mediated properties and potential in quantum operations. Achieving chiral quantum emission has traditionally required sophisticated techniques like high magnetic fields or cryogenic temperatures, and room-temperature circularly polarized luminescence (CPL) from individual quantum emitters is rarely reported. Here, it is shown that certain CsPbI3 perovskite quantum dots (PQDs) exhibit both room-temperature quantum emission and intrinsic CPL. Density functional theory (DFT) reveals that structural helicity and defects in PQDs induce band splitting, directly linking broken lattice symmetry to the observed chiroptical activity. By synthesizing PQDs with irregular shapes and reduced crystallinity, an unprecedented luminescence dissymmetry factor (glum) is achieved up to 0.41 without sacrificing the bright single-photon emission properties of PQDs. These findings establish PQDs as highly promising room-temperature chiral quantum emitters, paving the way for their application in scalable chiral quantum nanophotonics and quantum manipulation.

With the growing importance of displays, reducing their power consumption has become crucial for developing energy‐efficient photonic–electronic platforms. Conventional light emitting diodes (LEDs) rely on external polarizers and waveplates to control light polarization in displays, but these optics cause at least half of the incident energy of the LEDs to be lost, demanding higher drive currents and accelerating degradation. Generating circularly polarized light (CPL) directly at the source offers a low‐power alternative by eliminating such optical losses and enabling direct spin–photon interfaces. Recently, chiral metal halide perovskites (MHPs) have emerged as efficient, solution‐processable semiconductors that intrinsically couple light polarization and spin. Their strong spin–orbit coupling and broken inversion symmetry enable spin‐selective charge transport via the chiral‐induced spin selectivity effect, allowing both spin manipulation and its impact on emission to be observed within the same layer. In colloidal nanocrystal form they can emit CPL with high photoluminescence quantum yield, making them promising candidates for chiral light emission, although their use is still limited by low polarization anisotropy. This perspective discusses intrinsic and extrinsic routes to achieve circularly polarized electroluminescence (CP‐EL) using chiral MHPs, highlights progress in low‐dimensional films and chiral‐ligand nanocrystals, and discusses prospects for room‐temperature spin control and filter‐free, spin‐LEDs for next‐generation energy‐efficient optoelectronic displays.

Chiral halide perovskites have attracted considerable attention because of their chiroptical, second-harmonic generation, and ferroelectricity properties and their potential application in chiroptoelectronics and chiral spintronics. However, the fundamental research of these properties is insufficient. In this work, chiral perovskites were synthesized using precursor solutions with various stoichiometric ratios ⟨n⟩. The chiral perovskite film prepared from the solution with ⟨n⟩ = 1 is composed of (R-/S-/rac-MBA)2PbBr4, whereas the films prepared from the solutions with ⟨n⟩ larger than 1 are a mixture of (R-/S-/rac-MBA)2(CsMA)n-1PbnBr3n+1 with n = 1 and large n values. A photoluminescence quantum yield of approximately 90 was obtained. Symmetric circular dichroism (CD) spectra were observed without an external magnetic field. Under various magnetic fields, magnetic field-induced CD features are superimposed with the intrinsic chirality-induced CD features. For the ⟨n⟩ = 1 chiral perovskite film, the energy level splitting induced by chiral molecules are a few 10 μeV, whereas the energy level splitting induced by magnetic fields are at the range of ∼-250 to ∼250 μeV. Circularly polarized photoluminescence spectra were observed at room temperature and associated with the spin-preserved energy funneling from highly energetic phases to the lower energetic phases.

Chiral inorganic nanomaterial-based circularly polarized luminescence (CPL) materials have shown substantial promise in multiple research areas. However, the luminescence dissymmetry factor (glum), a key parameter for CPL, is far from satisfactory, especially for inorganic molecules with high luminescent quantum efficiency and diverse shapes and sizes. Obtaining large glum values is an urgent and crucial task in the field of CPL research. Among different approaches, the combination of inorganic nanomaterials and chiral nematic liquid crystals (N*-LCs) offers distinct advantages in achieving high glum values due to their distinctive optical characteristics and remarkable versatility. This concise review systematically investigates the recent advancements in CPL-active materials consisting of perovskites and N*-LCs. It elaborates on their preparation techniques, optical characteristics, and potential applications. Additionally, a brief outlook on their future development is offered. It is expected that this combination will assume an increasingly significant role in the CPL research field and attract more researchers to explore this area.

Circularly polarized (CP) coherent light sources are of great potential for various advanced optical applications spanning displays/imaging to data processing/encryption and quantum communication. Here, the first demonstration of CP amplified spontaneous emission (ASE)/lasing from a free‐standing and flexible membrane device is reported. The membrane device consists of perovskite nanocrystals (PNCs) and cholesteric liquid crystals (CLCs) layers sandwiched within a Fabry–Pérot (F–P) cavity architecture. The chiral liquid crystal cavity enables the generation of CP light from the device. The device is completely solution‐processable and displays CP ASE with record dissymmetry factor (glum) as high as 1.4, which is 3 orders of magnitude higher as compared with glum of CP luminescence of chiral ligand‐capped colloidal PNCs. The device exhibits ultraflexibility as the ASE intensity remains unchanged after repeated 100 bending cycles and it is stable for more than 3 months with 80% of its original intensity. Furthermore, the ultraflexibility enables the generation of ASE from various objects of different geometric surfaces covered with the flexible perovskite membrane device. This work not only demonstrates the first CP ASE from a PNCs membrane with extremely high glum but also opens the door toward the fabrication of ultraflexible, extremely stable, and all solution‐processable perovskite chiral laser devices.

Chiral organic‐inorganic hybrid perovskites have recently emerged as a promising new category of materials that display mirror optical signal responses, making them highly suitable for various applications in chiral nonlinear optics and circularly polarized luminescence emitters. However, there is a scarcity of reports on chiral hybrid perovskite materials that simultaneously possess substantial chiral second‐harmonic generation and a high asymmetric luminescence factor. In this study, 1D chiral lead‐bromide perovskites, namely (R‐/S‐2‐EP)PbBr4 have successfully synthesized and conducted a systematic investigation of their properties in terms of chiral second harmonic generation and circularly polarized luminescence. The effective second‐order nonlinear optical coefficient of (R‐2‐EP)PbBr4 is 0.33 pm V−1, along with a high laser damage threshold (LDT) of 5.42 mJ cm−2. Most importantly, both (R‐2‐EP)PbBr4 and (S‐2‐EP)PbBr4 demonstrate circularly polarized emission with a high dissymmetry factor glum of 0.03, which is the highest value among reported lead‐bromide chiral perovskites to date. These findings open new avenues for the development of high‐performance chiral materials for nonlinear chiroptical and circularly polarized luminescence emitters applications.

Spin injection sans magnetism Light-emitting diodes (LEDs) that emit circularly polarized light (spin-LEDs) have potential applications in in three-dimensional displays, bioencoding, and tomography. The requisite spin polarization of the charge carriers is usually achieved with ferromagnetic contacts and applied magnetic fields, but Kim et al. report on a room-temperature spin-LED that relies instead on a chiral-induced spin selectivity organic layer. This layer selectively injected spin-polarized holes into metal halide perovskite nanocrystals, where they radiatively recombined with unpolarized electrons with an efficiency of 2.6%. Science, this issue p. 1129 Spin-polarized light-emitting diodes based on metal halide perovskites operate at room temperature without a magnetic field. In traditional optoelectronic approaches, control over spin, charge, and light requires the use of both electrical and magnetic fields. In a spin-polarized light-emitting diode (spin-LED), charges are injected, and circularly polarized light is emitted from spin-polarized carrier pairs. Typically, the injection of carriers occurs with the application of an electric field, whereas spin polarization can be achieved using an applied magnetic field or polarized ferromagnetic contacts. We used chiral-induced spin selectivity (CISS) to produce spin-polarized carriers and demonstrate a spin-LED that operates at room temperature without magnetic fields or ferromagnetic contacts. The CISS layer consists of oriented, self-assembled small chiral molecules within a layered organic-inorganic metal-halide hybrid semiconductor framework. The spin-LED achieves ±2.6% circularly polarized electroluminescence at room temperature.

… we demonstrate spin injection across chiral halide perovskite/III–V interfaces achieving spin … c-HP can in fact be easily integrated with a III–V LED structure to transform it to a spin-LED. …

We developed type-II core-shell nanocrystals (NCs) with a chiral low-dimensional perovskite shell and an achiral 3D MAPbBr3 core. The core-shell NCs exhibit spin-polarized luminescence at the first excitation band of the achiral core, which is due to the chiral-induced spin selectivity (CISS) effect-governed spin-dependent shell-to-core electron transportation and the subsequent electron-hole recombination in the core. The preferred spin state of the transferred electrons is determined by the handness of the chiral shell. For the core-shell NCs film, a photoluminescence quantum yield (PLQY) of 54% and a circularly polarized luminescence (CPL) with a maximum |glum| of 4.0 × 10-3 are obtained at room temperature. Finally, we achieved a spin-polarized light-emitting diode (spin-LED), affording a circularly polarized electroluminescence (CP-EL) with a |gCP-EL|of 6.0 × 10-3 under ambient conditions.

Spin light‐emitting diodes (Spin‐LEDs) can directly generate circularly polarized luminescence (CPL) at room temperature without external magnetic fields, offering promising applications in quantum communication, 3D displays, and biomedical imaging. Recent advances in chiral nanomaterials, particularly chiral perovskites, chiral colloidal quantum dots (QDs), and chiral metal–organic frameworks (CMOFs), have significantly improved device performance through the chirality‐induced spin selectivity (CISS) effect. This review systematically examines the fundamental mechanisms of CPL generation, including spin–orbit coupling, band splitting, and optical selection rules in chiral materials. Recent developments in material design strategies are analyzed, from low‐dimensional chiral perovskites to surface‐modified colloidal QDs, and emerging CMOFs with tunable pore structures, and their applications in integrated and separated chiral‐emissive layer device architectures. Current Spin‐LEDs have achieved external quantum efficiency (EQE) over 22%, and the circularly polarized electroluminescence dissymmetry factors (gCP‐EL) have reached the level of 10−1. However, challenges remain in understanding spin relaxation mechanisms, balancing luminescence efficiency and polarization, and improving material stability. This review summarizes the relevant physical mechanisms, material and device optimization strategies, and explores the potential trends for advancing high‐performance Spin‐LEDs in practical optoelectronic applications.

Chiral‐induced spin selectivity (CISS) effect provides innovative approach to spintronics and quantum‐based devices for chiral materials. Different from the conventional ferromagnetic devices, the application of CISS effect is potential to operate under room temperature and zero applied magnetic field. Low dimensional chiral perovskites by introducing chiral amines are beginning to show significant CISS effect for spin injection, but research on chiral perovskites is still in its infancy, especially on spin‐light emitting diode (spin‐LED) construction. Here, the spin‐QLEDs enabled by 2D chiral perovskites as CISS layer for spin‐dependent carrier injection and CdSe/ZnS quantum dots (QDs) as light emitting layer are reported. The regulation pattern of the chirality and thickness of chiral perovskites, which affects the circularly polarized electroluminescence (CP‐EL) emission of spin‐QLED, is discovered. Notably, the spin injection polarization of 2D chiral perovskites is higher than 80% and the CP‐EL asymmetric factor (gCP‐EL) achieves up to 1.6 × 10−2. Consequently, this work opens up a new and effective approach for high‐performance spin‐LEDs.

… perovskite with spin-polarized fluorescence and its spin-LED at room temperature based on chiral-induced spin … By incorporating an achiral organic spacer in a chiral quasi- 2D film, we …

Chiral perovskites play a pivotal role in spintronics and optoelectronic systems attributed to their chiral-induced spin selectivity (CISS) effect. Specifically, they allow for spin-polarized charge transport in spin light-emitting diodes (LEDs), yielding circularly polarized electroluminescence at room temperature without external magnetic fields. However, chiral lead bromide-based perovskites have yet to achieve high-performance green emissive spin-LEDs, owing to limited CISS effects and charge transport. Herein, we employ dimensional regulation and Sn2+-doping to optimize chiral bromide-based perovskite architecture for green emissive spin-LEDs. The optimized (PEA)x(S/R-PRDA)2–xSn0.1Pb0.9Br4 chiral perovskite film exhibits an enhanced CISS effect, higher hole mobility, and better energy level alignment with the emissive layer. These improvements allow us to fabricate green emissive spin-LEDs with an external quantum efficiency (EQE) of 5.7% and an asymmetry factor |gCP‑EL| of 1.1 × 10–3. This work highlights the importance of tailored perovskite architectures and doping strategies in advancing spintronics for optoelectronic applications.

Low temperature solution‐processible chiral metal halide perovskites, which posse the innately chiral‐induced spin orbit coupling (CISOC), are valuable for the realization of room temperature single junctions‐based spin‐light‐emitting diodes (spin‐LEDs), without involving integrated optics and ferromagnetic electrodes. The current challenging primarily lies on the development of high‐performance spin‐LEDs and the demonstration of the chiral‐induced spin selectivity (CISS). Herein, chiral organic cation based quasi‐2D perovskite films with prominently circularly polarized luminescence and bright emissions are fabricated for the application of room‐temperature spin‐LEDs. A remarkable external quantum efficiency (EQE) of 15.42% and circularly polarized electroluminescence (CP‐EL) of 4.98% are well achieved in ambient condition. With studies of spin‐related exciton states and magneto‐photoluminescence (magneto‐PL), the spin‐lifetime (τs) is estimated to be 20 ps. This work has greatly promoted the present growth for the high‐performance chiral perovskites spin‐LEDs.

The phenomenon of chiral symmetry breaking during the crystallization of achiral molecules or ions, which leads to the formation of controllable enantiomerically pure crystals, has garnered significant interest but remains a challenge to fully overcome. This presents a particularly formidable obstacle in the creation of three-dimensional (3D) structured chiral all-inorganic perovskites, further complicated by their achiral crystalline space groups. In this report, we successfully synthesized right- or left-handed (P/M) chiral 3D P/M-CsPbX3 (X = Cl, Cl-Br, Br, Br-I) perovskite subnanowires (SNWs), in which Pb(II) can be partially substituted by hetero ions, such as Cu(II), Sn(II), and Mn(II). The selective control of the SNW handedness was achieved through the strategic incorporation of trace chiral amine enantiomers. The chiroptical activity arises from the helical structure of the SNWs. The mechanisms underlying the formation of this chiral structure were systematically investigated and interpreted by using a thermodynamic model. We utilized the chiral P/M-CsPbBr3 SNWs to fabricate circularly polarized light (CPL) photodetectors, which exhibited an impressive photocurrent dissymmetry factor (gIph) of 0.75. In the field of spin light-emitting diodes (spin-LEDs), circularly polarized electroluminescence (CPEL) was accomplished by employing the SNWs as a dual-functional material that provides both chiral-induced spin selectivity (CISS) and CPL emission capabilities.

Spin-LEDs have been a central topic in semiconductor spintronics research and represent a promising avenue for advanced optoelectronic devices and applications. The future advancements of spin-LEDs will undoubtedly hinge on the generation and manipulation of spin-polarized population at room temperature. In this research, we elucidate the development of room-temperature spin-LEDs using quasi-2D perovskites, based on the chiral-induced spin selectivity (CISS) effect. During the carrier transfer from the chiral n2 phase to the randomly oriented high-n phase caused by the bandgap gradient distribution, CISS works to generate non-equilibrium spin population, leading to room-temperature spin-polarized fluorescence. A spin-polarization of ∼93% is observed for the films. Finally, we realize spin-LEDs at room temperature, exhibiting a |gCP-EL| value of 0.05 and an EQE of 3.8%. This work highlights the potential of integrating dual ligands to optimize the phase distribution and crystalline orientation in quasi-2D films to achieve efficient CISS for spin-LED applications.

In chiral hybrid perovskites (CHPs), the generation of polarized spin current and the manipulation of spin exciton recombination are expected to produce circularly polarized electroluminescence (CP‐EL) through chiral‐induced spin selectivity (CISS). It opens a new avenue for developing single junction spin light‐emitting diodes (spin‐LEDs). The recent challenge lies primarily in balancing device performance and CP‐EL polarization. Beyond this, blue spin‐LEDs have not been fully realized. It lacks studies for interior spin‐chiroptical properties. Herein, a promising chirality transfer methodology is initiated for fabricating sky‐blue (≈491 nm) spin‐LEDs using synthesized chiral ionic liquids (CILs). They on one side yield the material passivation, giving rise to the chiroptical and electroluminescence (EL) properties. An optimal external quantum efficiency (EQE) of 13.0% with a dissymmetry factor of 0.158 for CP‐EL is obtained. Importantly, this method leads to the elevation of chiral‐induced spin orbit coupling (CISOC) strength up to 0.9717 eV A, with a long decay lifetime over 1 ns for the polarization. A large polarized spin current of approximately 75% is achieved in ambient conditions. This work unlocks the blue spin‐LEDs, with further construction for the spin‐chiroptics and device performance relationship.

Chiral hybrid perovskites (CHPs) are very promising for room temperature spin‐light emitting diodes (spin‐LEDs) because of the chiral‐induced spin orbit coupling (CISOC) and the helicity‐dependent carrier transport. The chiral‐achiral synergistic method has been recognized as a critical and successful pathway for developing high‐performance spin‐LEDs. Nonetheless, it remains an absence of any studies to demonstrate and elucidate the relationship between chiral perovskite spin‐LEDs’ performance and magneto‐chiroptical properties. Herein, high‐performance spin‐LEDs are being designed and fabricated using the synergistic method. A combination of experimental and theoretical study is performed systematically toward understanding critical spin‐related chiroptical properties, for instance, spin lifetimes, CISOC strengths, and magnetic transition dipole moments. To tune the chiral organic constituent is found to be decisive for degrees of circularly polarized electroluminescence (CP‐EL) and magneto‐chiroptical properties of CHPs. This insightful study, for the first time, unlocks the correlation between the chiral perovskite spin‐LEDs’ performance and spin‐dependent chiroptical properties due to the synergistic effect.

… in the efficient spin-polarized carriers, making chiral perovskites … and fabricating room-temperature spin-LEDs that can work … on the chiral perovskites and their CPL emission, spin-LEDs …

Chiral hybrid perovskites are promising materials for spin-polarized light-emitting diodes (spin-LEDs), using the chirality-induced spin selectivity (CISS) effect to generate circularly polarized electroluminescence without a ferromagnetic electrode. However, the relation between material structure, spin dynamics, and device performance remains unclear. Here, we use magneto-electroluminescence (MEL) to probe spin-dependent processes in chiral perovskite spin-LEDs. We show that spin polarization can be enhanced through two strategies: tuning the content ratio of chiral components to strengthen spin filtering, and optimizing film morphology via thermal annealing to improve spin transfer efficiency. Devices with a higher fraction of the chiral 2D phase exhibit stronger CISS-mediated spin injection, while smoother, fine-grained films better preserve spin polarization during transfer to the emitting sites. Our findings clarify the material-spin-performance relationship in chiral perovskites and provide practical guidelines for developing efficient spin-optoelectronic devices.

… the chirality transfer from a chiral molecule to chiral perovskite. As … of chiral MBABr and reduced-dimensional chiral perovskite (… (a) Spin-polarized charge injection in spin-LED device …

Abstract Chiral quasi‐2D perovskite single crystals (SCs) were investigated for their circular polarized light (CPL) detecting capability. Quasi‐2D chiral perovskites, [(R)‐β‐MPA]2MAPb2I7 ((R)‐β‐MPA=(R)‐(+)‐β‐methylphenethylamine, MA=methylammonium), have intrinsic chirality and the capability to distinguish different polarization states of CPL photons. Corresponding quasi‐2D SCs CPL photodetector exhibit excellent detection performance. In particular, our device responsivity is almost one order of magnitude higher than the reported 2D perovskite CPL detectors to date. The crystallization dynamics of the film were modulated to facilitate its carrier transport. Parallel oriented perovskite films with a homogeneous energy landscape is crucial to maximize the carrier collection efficiency. The photodetector also exhibits superior mechanical flexibility and durability, representing a promising candidate for sensitive and robust CPL photodetectors.

… , a CPL photodetector based on 1D chiral perovskites was … 1D chiral perovskites have the largest molar ratio of chiral … Chiral perovskites exhibit asymmetric circular polarization emission …

A helical one-dimensional lead halide perovskite structure shown to detect circularly polarized light as an efficient photodiode. Detection of circularly polarized light (CPL) has a high potential for development of various optical technologies. Conventional photodetectors require optical polarizers on the device to detect polarized light, and this causes substantial losses of sensitivity and resolution in light detection. Here, we report direct CPL detection by a photodiode using a helical one-dimensional (1D) structure of lead halide perovskites composed of naphthylethylamine-based chiral organic cations. The 1D structure with face-sharing (PbI6)4− octahedral chains whose helicity is largely affected by chiral cations shows intense circular dichroism (CD) signals over 3000 mdeg at 395 nm with the highly anisotropy factor (gCD) of 0.04. This high CD enables photocurrent detection with effective discrimination between left-handed and right-handed CPLs. The CPL detector based on this 1D perovskite achieved the highest polarization discrimination ratio of 25.4, which largely surpasses the direct detecting CPL devices (<4) using chiral plasmonic metamaterials and organic materials.

Polarization‐sensitive photodetectors are gaining numerous attention since polarization detection is important in geological remote sensing, atmospheric monitoring, military recon, and medical examination. Among various reported photoactive materials for photodetectors, metal halide perovskites have outstanding advantages such as tunable band gaps, excellent optoelectronic properties, and easy fabrication. Moreover, the characteristics of crystal structure anisotropy and controllable growth orientation of perovskite crystals endow the perovskite photodetector with the ability to identify light polarization states. This review outlines the recent research progress of perovskite photodetectors on polarization‐sensitive detection. Firstly, key device parameters of polarization‐sensitive detection are introduced. Then, the recent progress of polarization‐sensitive perovskite detectors in the field of linear and circular polarization is reviewed according to the different principles of polarization response. Finally, the challenges of polarization‐sensitive perovskite photodetector are discussed.

Structural engineering in multiple scales permits the integration of exotic properties into a single material, which boosts the development of ultracompact multifunctional devices. Layered perovskites are capable of cross-linking efficient carrier transport originating from few-layer perovskite frameworks with extended functionalities contributed by designable bulky organic cations and nanostructures, thus providing a platform for multiscale material engineering. Herein, high-performance Stokes-parameter photodetectors for arbitrary polarized light detection are realized on the basis of solution-processed chiral-perovskite nanowire arrays. The chiral ammonium cations intercalated between the perovskite layers are responsive to circularly polarized light with a maximum anisotropy factor of 0.15, while the strictly aligned nanowires with the anisotropic dielectric function result in a large polarized ratio of 1.6 to linearly polarized light. Single crystallinity and pure crystallographic orientation permit efficient in-plane carrier transport along the nanowires, yielding a responsivity of 47.1 A W-1 and a detectivity of 1.24 × 1013 Jones. By synergy of linear- and circular-polarization response with high optoelectronic performance for providing sufficient photocurrent contrasts, Stokes-parameter photodetection is demonstrated on these nanowires. Our Stokes-parameter photodetectors with a small footprint and high performances present promising applications toward polarization imaging.

Circularly\npolarized light (CPL) has considerable technological\npotential, from quantum computing to bioimaging. To maximize the opportunity,\nhigh performance photodetectors that can directly distinguish left-handed\nand right-handed circularly polarized light are needed. Hybrid organic–inorganic\nperovskites containing chiral organic ligands are an emerging candidate\nfor the active material in CPL photodetecting devices, but current\nstudies suggest there to be a trade-off between the ability to differentially\nabsorb CPL and photocurrent responsivity in chiral perovskites devices.\nHere, we report a CPL detector based on quasi two-dimensional (quasi-2D)\nchiral perovskite films. We find it is possible to generate materials\nwhere the circular dichroism (CD) is comparable in both 2D and quasi-2D\nfilms, while the responsivity of the photodetector improves for the\nlatter. Given this, we are able to showcase a CPL photodetector that\nexhibits both a high dissymmetry factor of 0.15 and a high responsivity\nof 15.7 A W–1. We believe our data further advocates\nthe potential of chiral perovskites in CPL-dependent photonic technologies.

Circularly polarized light (CPL) plays an important role in many photonic techniques, including tomographic scanning based on circular polarization ellipsometry, optical communication and information of spin, and quantum-based optical calculation and information processing. To fully exploit the functions of CPL in these fields, integrated photoelectric sensors capable of detecting CPL are essential. Photodetectors based on chiral materials can directly detect CPL due to their intrinsic optical activity, without the need to be coupled with polarizers and quarter-wave plates as in conventional photodetectors. This review summarizes the recent research progress in CPL photodetectors based on chiral materials. We first briefly introduce the CPL photodetectors based on different types of chiral materials and their working principles. Finally, current challenges and future opportunities in the development of CPL photodetectors are prospected.

… and under right-handed circular polarized (RCP) and left-handed circular polarized (LCP) … photocurrent of the (R-NEA)PbI 3 photodetector can reach 1.4 pA under a power density of …

Two‐dimensional (2D) perovskites hold great promise for optoelectronic devices due to the flexible tunability of chiral optical activity and optoelectronic properties. However, the trade‐off between strong chiral effect and efficient charge transport restricts their development in high‐performance circularly polarized light (CPL) detection. In this work, a tailored achiral‐chiral cation mixing strategy is proposed to improve the intermolecular forces and out‐of‐plane octahedral tilt in the chiral perovskite, which effectively promotes chirality transfer and van der Waals forces tuned vertical growth. Further, a chiral 2D perovskite‐based CPL photodetector is constructed with balanced high absorption anisotropy (gabs) and photocurrent anisotropy (gIph). Compared with materials obtained with pure chiral cations, the maximum gabs of this chiral 2D perovskite increased by 7.33 times. The enhanced chiroptical activity and in‐plane transport in vertically oriented chiral 2D perovskites endowed the self‐powered CPL device with outstanding performance and a record gIph of 0.72. This work opens a reasonable paradigm of chiral 2D perovskite photodetectors in information encryption.

The chiroptical properties of perovskites offer a direct means for optical detection and discrimination of polarization information. inefficient chirality transfer from organic chiral spacers to the inorganic framework leads to generally low anisotropy factors (gres) in circularly polarized light (CPL) detection. In contrast, 1D chiral perovskites exhibit superior chirality, thereby generating significantly enhanced CPL responses. Centimeter‐scaled and block‐shaped 1D chiral perovskite single crystals (SCs) (R)‐/(S)‐AMEPYPb2Br6 (AMEPY = 2‐aminoethyl‐1‐methylpyrrolidine) are grown, with intrinsic chirality for circularly polarized light (CPL) discrimination. Theoretical analysis reveals that charge transport routes (intrachain/interchain) and efficiency are dynamically modulated by thermal lattice distortion and photoexcited states. By optimizing free‐carrier capture probability and trap‐state density, the resulting CPL photodetector demonstrates an anisotropy factor of 1.05 for (S)‐AMEPYPb2Br6 and −1.12 for (R)‐AMEPYPb2Br6 along the intrachain direction, representing a two‐fold improvement over reported perovskite materials. Equally importantly, A responsivity of 1.97 A W−1 and detectivity of 3.8 × 1012 Jones are also achieved, along with excellent bias and UV‐light stability, comparable to commercial diodes.

Chiral hybrid perovskites (CHPs), aggregating chirality and favorable semiconducting properties in one, have taken a prominent position in direct circularly polarized light detection (CPL). However, passive high circular polarization sensitivity (gres) photodetection in CHPs is still elusive and challenging. Benefitting from efficient control and turning of carrier transport of CHPs by dimensional engineering, here, we unprecedentedly proposed a chain-to-layer dimensionality engineering to realize high-gres passive photodetection. Two novel 2D layered CHPs (R/S-PPA)EAPbBr4 (2R/2S) (PPA = 1-phenylpropylamine, EA = ethylammonium) are successfully synthesized by alloying an EA cation with small steric hindrance into the chained CHPs (R/S-PPA)PbBr3 (1R/1S). Particularly, compared with the neglectable photoresponse in 1R, the obtained 2R by chain-to-layer dimensionality engineering gives rise to an excellent photoconductivity and robust polar photovoltage effect (PPE) with a giant open-circuit voltage of 2.5 V. Furthermore, such PPE promotes realizing an impressive gres in 2R up to 0.42 at zero bias because of the independent separation of photoexcited carriers, which is the highest value among the reported layered chiral perovskites. This work paves the way for the vigorous development of higher dimensional CHPs and will reveal their applications in the field of passive high-gres CPL detection.

… perovskite compounds with global chiral polarity can be obtained robustly by introducing chiral … Here, we designed bilayered chiral PHP (R/S-BPEA) 2 (formamidium)Pb 2 I 7 (RBFP and …

Conventional circularly polarized light (CPL) detectors face a grand challenge with device integration and miniaturization because of the need for complex optical components. Chiral perovskites have recently emerged as interesting materials for CPL detectors that do not require additional optical elements but struggle to achieve a high photocurrent dissymmetry factor (gIph). Herein, a simple and promising strategy is reported for high‐performance circularly polarized perovskite photodetectors (CP‐PPDs) with exceptionally high gIph. The CP‐PPDs are fabricated using perovskite single crystals in combination with free‐standing cholesteric liquid crystal polymer films (P‐CLC) that empower the device to trigger an optically selective response. By tuning the photonic bandgap of the P‐CLC film, the spectral response of the CP‐PPDs is tunable over a broad range of wavelengths. The devices show detectivities of 6.8 × 1013 and 5.1 × 1013 Jones at 520 and 405 nm, respectively. Importantly, the PDs exhibit high  gIph factors of up to 1.95 at 520 nm, which is the highest reported to date for CP‐PPDs. Furthermore, as a proof‐of‐concept, CP‐PPD arrays are demonstrated for use in image sensing.

Low-dimensional hybrid organic–inorganic perovskites (HOIPs) containing chiral organic ligands have recently emerged as promising candidates for circularly polarized light (CPL) detection, which can distinguish left- and right-handed CPL directly. However, the increase in responsivity and realization of self-powered CPL photodetector remain a challenge. Meanwhile, there is a trade-off between the photocurrent responsivity and the ability to differentially absorb CPL in detectors based on these low-dimensional perovskites. Herein, we report the CPL photodetector based on chiral quasi-2D perovskite films (S/R-MBA)2MAPb2I7 and propose a crystallization regulation method using dimethyl sulfoxide (DMSO) and methylammonium thiocyanate (MASCN). We found that the photoelectric response capability and circular dichroism (CD) intensities of chiral quasi-2D perovskite can be enhanced simultaneously by the improved crystallinity and surface morphology of chiral films. Meanwhile, the formation of the tetragonal perovskite structure leads to symmetry-breaking distortion of the inorganic frameworks, further enhancing the chirality of the perovskite films. In addition, the distribution of n-phase can be tuned by DMSO and MASCN to form graded band alignment, effectively promoting the charge transfer in perovskite. As a result, a self-powered CPL photodetector with a high responsivity of 0.82 A/W and an anisotropy factor of 0.09 at 0 V bias is obtained. To the best of our knowledge, it is the first attempt to enhance the CD characteristics of chiral quasi-2D perovskite films. We believe our work further advances the research of low-dimensional chiral perovskite films in the field of CPL detection.

Direct detection of circularly polarized light (CPL) holds great promise for the development of various optical technologies. Chiral 2D organic-inorganic halide perovskites make it possible to fabricate CPL-sensitive photodetectors. However, selectively detecting left-handed circularly polarized (LCP) and right-handed circularly polarized (RCP) light remains a significant challenge. Herein, we demonstrate a greatly enhanced distinguishability of photodiode-type CPL photodetectors based on chiral 2D perovskites with mixed chiral aryl (R)-(+),(S)-(-)-α-methylbenzylammonium (R,S-MBA) and achiral alkyl n-butylammonium (nBA) cations. The (R,S-MBA0.5nBA0.5)2PbI4 perovskites exhibit a 10-fold increase in circular dichroism signals compared to (R,S-MBA)2PbI4 perovskites. The CPL photodetectors based on the mixed-cation perovskites exhibit self-powered capabilities with a specific detectivity of 2.45 × 1012 Jones at a 0 V bias. Notably, these devices show high distinguishability (gres) factors of -0.58 and +0.54 based on (R,S-MBA0.5nBA0.5)2PbI4 perovskites, respectively, surpassing the performance of (R-MBA)2PbI4-based devices by over 3-fold and setting a record for CPL detectors based on chiral 2D n = 1 perovskites.

Chiral metal halide perovskites (CMHPs) have recently shown great potential for direct circularly polarized light (CPL) detection. However, owing to the limited cutoff wavelength edge of these CMHPs, most of the detectors presented thus far are characterized only in the ultraviolet and visible range; CMHPs that target at the near-infrared (NIR) region are still greatly desired. Here, we design a novel CMHP heterostructure, synthesized via solution-processed epitaxial growth of crystalline 3D MAPbI3 on a 2D chiral (R-BPEA)2PbI4 (R-BPEA = (R)-1-(4-bromophenyl)ethylammonium) crystal, and provide the first demonstration of self-powered direct NIR-CPL detection. Compared with individual chiral (R-BPEA)2PbI4, the heterostructure not only retains the spin selectivity but also allows much broader absorbance, especially beyond 780 nm, where the (R-BPEA)2PbI4 cannot absorb. Furthermore, the built-in electric potential in the heterojunction forces spontaneous separation/transport of photogenerated carriers, enabling the fabrication of devices operating without external energy supply. By making use of the abovementioned advantages, the self-powered CPL detectors of the (R-BPEA)2PbI4/MAPbI3 heterostructures hence show competitive circular polarization sensitivity at 785 nm with a high anisotropy factor of up to 0.25. In addition, a large on/off switching ratio of ∼105 and an impressive detectivity of ∼1010 Jones are also achieved. As a pioneer study, our results may broaden the material scope for future chiroptical devices based on CMHPs.

Circularly polarized light (CPL) detection has extensive applications in the fields of optoelectronic devices, information security, biomedical imaging, and so on. Due to their unique structure, the (R)‐(+)‐α‐methylbenzylamine (R‐MBA) and (S)‐(−)‐α‐methylbenzylamine (S‐MBA) are chosen as a chiral cationic template. The chiral 2D perovskite (R/S‐MBA)2PbI4 single crystals exhibit high absorption and prominent circular dichroism (CD) signals, highlighting their significant potential for CPL detectors. In this study, a self‐powered (R/S‐MBA)2PbI4 circularly polarized photodetector is reported. The responsivity (R), specific detectivity (D*), and light on/off ratio of the (R‐MBA)2PbI4 device under 532 nm right‐handed circularly polarized (RCP) light at 0 V bias voltage are 58 mA W−1, 2.96 × 1011 Jones, and 568. These values of the (S‐MBA)2PbI4 device are 61 mA W−1, 3.09 × 1011 Jones, and 478 under left‐handed circularly polarized (LCP) light at 0 V bias voltage. The photocurrent anisotropy factor (gIph) for (R‐MBA)2PbI4 and (S‐MBA)2PbI4 is exhibited to be 0.03 and 0.05, demonstrating a strong selectivity for CPL. The biomimetic CPL imaging system, bio‐inspired by mantis shrimp vision, further provides its practical potential in high‐resolution polarization‐sensitive applications. The research offers a solution for next‐generation CPL detection technologies.

Polarization detection plays an essential role in a wide range of fields, including target identification, 3D reconstruction, and robotic vision. Self‐driven on‐chip full‐Stokes photodetectors are urgently required to meet the trend of miniaturization and integration. Nevertheless, how to fulfill efficient circular and linear polarimetry simultaneously with sufficient recognition effectiveness in a compact device is a great challenge. Herein, a patterned chiral perovskite film is fabricated by imprinting strategy, and vertically‐structured self‐driven Stokes photodetector is demonstrated, which can recognize various polarization states at 0 V. Through patterned design of the chiral perovskite film by integrating circle and nanowire structure, flexible tuning of circular and linear polarization components within the detector is achieved, enabling the detector to strike a balance between circular and linear polarization detection ability when recognizing arbitrary polarization light. The maximum circular polarization sensitivity factor and linear polarization ratio can reach 0.125 and 1.5, respectively. By optimizing well‐defined patterned shape, the resultant detector can recognize polarized light with an average recognition error <7%. This work opens an avenue toward the fabrication of self‐driven filterless Stokes detectors based on patterned chiral perovskite film for accurate detection of arbitrary polarization states.

… and left circularly polarized light, respectively.(2)g lum =(I L -I R )/[(1/2)(I L +I R )] … chiral metal halides (R/S-1-PPA) 2 MnBr 4 . We measured the circularly polarized photoluminescence …

Generating circularly polarized luminescence (CPL) with simultaneous high photoluminescence quantum yield (PLQY) and dissymmetry factor (glum) is difficult due to usually unmatched electric transition dipole moment (µ) and magnetic transition dipole moment (m) of materials. Herein we tackle this issue by playing a "cascade cationic insertion" trick to achieve strong CPL (with PLQY of ~ 100%) in lead-free metal halides with high glum values reaching -2.3×10-2 without using any chiral inducers. Achiral solvents of hydrochloric acid (HCl) and N, N-dimethylformamide (DMF) infiltrate the crystal lattice via asymmetric hydrogen bonding, distorting the perovskite structure to induce the "intrinsic" chirality. Surprisingly, additional insertion of Cs+ cation to substitute partial (CH3)2NH2+ transforms the chiral space group to achiral but the crystal maintains chiroptical activity. Further doping of Sb3+ stimulates strong photoluminescence as a result of self-trapped excitons (STEs) formation without disturbing the crystal framework. The chiral perovskites of indium-antimony chlorides embedded on LEDs chips demonstrate promising potential as CPL emitters. Our work presents rare cases of chiroptical activity of highly luminescent perovskites from only achiral building blocks via spontaneous resolution as a result of symmetry breaking.

Circularly polarized luminescence (CPL) materials are highly attractive for next-generation photonic and information technologies, yet achieving both a large luminescence dissymmetry factor (glum) and near-unity photoluminescence quantum yield (PLQY) remains challenging in lead-free chiral metal halides. Here, we report a pair of zero-dimensional chiral indium-based chloride enantiomers, (R/S-AQ)2In1-xSbxCl7 (AQ = 3-aminoquinuclidine), enabled by Sb3+-doping. A dense interfacial N-H···Cl hydrogen-bond network strengthens organic-inorganic coupling and is likely to facilitate chiral transfer, while Sb3+ incorporation activates highly efficient broadband self-trapped exciton emission. As a result, the enantiomers exhibit near-unity PLQY (up to 99.32%) together with mirror-image CPL signals with |glum| ≈ 2.0 × 10-2. A CP-LED based on a commercial 280 nm UV chip shows stable device emission under electrical driving while retaining circular polarization. Our work demonstrates an effective strategy for co-optimizing efficiency and polarization in chiral metal halides toward practical CPL devices.

Chiral materials with circularly polarized luminescence (CPL) are currently attracting great attention for their wide applications in bioresponsive imaging, 3D displays, and storage of information. Herein, CPL‐active enantiomorphic hybrids (R)‐ and (S)‐C6H15Cl2NO⋅SbCl5 are obtained by self‐assembling chiral R/S‐(3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride with antimony(III) chloride, giving a 0D structure with SbCl5 pyramids isolated by (3‐chloro‐2‐hydroxypropyl)trimethylammonium chloride cations. The formed enantiomers exhibit brilliant orange emission peaked at 604 nm with photoluminescence quantum yield as high as 71.2%, originating from the self‐trapped exciton emission demonstrated by photophysical characterization. Due to the existence of chiral organic cations, the enantiomers exhibit strong chiral‐optical properties with mirror‐image circular dichroism signals in ground state and obvious CPL activity with the dissymmetry factor glum of 2.5 × 10−4 and −1.6 × 10−4 for R‐type and S‐type, respectively. It should be mentioned that these are the first reported 0D hybrids with CPL‐activity. This work paves an avenue for developing eco‐friendly CPL materials with highly ‐efficient luminescence.

Stimulus‐responsive materials that exhibit efficient circularly polarized luminescence (CPL) have gained much interest for application in advanced smart photonics. Herein, the CPL‐active enantiomorphic 0D Sb3+‐doped (R/S)2InCl7 (R/S = R/S‐2‐methylpiperazine) are synthesized via a solution method. They show efficient broadband yellow emission with a near‐unity photoluminescence quantum yield and a CPL asymmetry factor of 1.7 × 10−3. Their fascinating chiroptical activity should be attributed to the chirality transfer and self‐trapped exciton emission caused by strong electron–phonon interaction. Particularly, H2O‐induced structural transformation is demonstrated to obtain non‐emission of Sb3+‐doped (R/S)2InCl7·H2O after exposure to a humid environment. Importantly, Sb3+‐doped (R/S)2InCl7 exhibits unique nonlinear optical responses, and the rotation angle between the quarter‐wave plate and linearly polarized plate can regulate the reversible switching of Sb3+‐doped (R/S)2InCl7 between yellow emission and negligible luminescence. Moreover, a circularly polarized white light‐emitting diode is fabricated by combining blue phosphors BaMgAl10O17:Eu2+, and the device exhibits tunable switching control of positive and warm white light by regulating the rotation angle of linear polarizer plate. Based on the tunable optical responses of Sb3+‐doped (R/S)2InCl7, a programmable multi‐mode fluorescence encoding system is constructed, and four‐level information encryption and three‐level encrypted 3D color codes are also realized in a further proof‐of‐concept experiment.

The pursuit of chiral lead-free metal halides with both high photoluminescence quantum yield (PLQY) and large luminescence dissymmetry factor (glum) remains a priority for designing efficient circularly polarized light sources. However, a tradeoff exists between PLQY and glum in chiral materials due to the mismatched electric (μ) and magnetic transition dipole moment (m). Herein, we address this contradiction and develop the efficient circularly polarized luminescence (CPL) emitters through structural dimension modulation. By tuning the size and polarization of chiral organic cations and employing the cascade cationic insertion strategy, 0D, 1D and 3D indium-based chiral metal halides are constructed. These hybrids exhibit self-trapped excitons emission with near-unity PLQY, while the |glum| boosts exponentially from 10−3 to nearly 10−1 as the structural dimension increases from 0D to 3D, and the highest |glum| of 0.89 × 10−1 has been achieved. Structural analysis and theoretical calculation indicate the increased structural dimension promotes the formation of helical structure and enlarges magnetic transition dipole moment, thus resulting in improved CPL performance. Our research provides valuable insights on the relationship between glum and structural dimension, thus will advance the development of efficient CPL-active materials for practical applications. Designing efficient circularly polarized light sources requires a balance between the photoluminescence quantum yield and the luminescence dissymmetry factor. Here, the authors develop indium-based chiral metal halides with efficient CPL characteristics by modulating their structural dimensions.

Stimuli‐responsive circularly polarized luminescent materials have broad application prospects in fields such as information encryption and anti‐counterfeiting, chiral optoelectronic devices and so on. In this study, 0D antimony‐based halides enantiomer R ‐DMSO and S ‐DMSO with bright yellow fluorescence, were successfully prepared using R/S ‐3‐aminoquinine cyclic ammonium as the organic cation. Enantiomer R ‐DMSO and S ‐DMSO exhibit interesting self‐trapped excitons (STEs) emission and fascinating circular dichroism (CD) with photoluminescence quantum yield (PLQY) approaching 100%. In addition, enantiomer R ‐DMSO and S ‐DMSO exhibited significant circularly polarized luminescence (CPL) signals, with a measured luminescence dissymmetry factor () of approximately ±7.61 × 10 −4 . By immersing R/S ‐HCl in DMSO, it can be transformed into yellow fluorescence, its CPL signals are almost identical to R/S ‐DMSO. After heating at 110°C for 1 h in a vacuum oven, it is transformed back into R/S ‐HCl, this process achieves reversible switching of CPL signals. By utilizing this property, relevant applications of dual information encryption and anti‐counterfeiting have been carried out. In addition, UV pumped circularly polarized light‐emitting diode (CP‐LED) devices based on enantiomer R ‐DMSO and S ‐DMSO exhibit excellent luminescence performance, with of approximately 3.68 × 10 −3 and −3.85 × 10 −3 . This study provides a new approach for the development of stimuli‐responsive functional chiral antimony‐based hybrid halides.

Metal-halide perovskites are recently emerging as the promising alternative for CPL detection owing to their CPL-sensitive property induced by chiral organics and efficient charge transport of inorganic frameworks. However, most of these reported chiral perovskites involve high concentrations of toxic Pb which will become the potential bottleneck for their further application. Herein, we successfully developed two lead-free halide double perovskites, [( R )- β -MPA] 4 AgBiI 8 (( R )- β -MPA = ( R )-(+)- β -methylphenethylammonium, 1- R ), and [( S )- β -MPA] 4 AgBiI 8 (( S )- β -MPA = ( S )-(-)- β -methylphenethylammonium, 1- S ). Circular dichroism measurements reveal that these perovskites exhibit notable chirality induced by organic cations to distinguish different polarization states of CPL photons. Significantly, they present unique chiral polar photovoltaic, and resulting self-powered CPL detection without an external power source is unprecedentedly achieved. Furthermore, an anisotropy factor up to 0.3 is acquired for the self-powered CPL detection, reaching the highest value among reported chiral perovskites. This work suggests hybrid double perovskites are promising photoelectronic candidates, and provides a new approach for exploring new "green" circularly polarized light-sensitive materials with high perfromance .

… Among these, circularly polarized light (CPL), a prototypical chiral electromagnetic wave, … Realizing tunable white light emission in leadfree indium(III) bromine hybrid single crystals …

Chiral organic-inorganic hybrid metal halides as promising circularly polarized luminescence (CPL) emitter candidates hold great potential for high-definition displays and future spin-optoelectronics. The recent challenge lies primarily in developing high-performance red CPL emitters. Here, coupling the f-f transition characteristics of trivalent europium ions (Eu3+) with chirality, we construct the chiral Eu-based halides, (R/S-3BrMBA)3EuCl6, which exhibit strong and predictable red emission with large photoluminescence quantum yield (59.8%), narrow bandwidth (≈2 nm), long lifetime (≈2 ms), together with large dissymmetry factor |glum| of 1.84 × 10−2. Compared with the previously reported chiral metal halides, these chiral Eu-based halides show the highest red CPL brightness. Furthermore, the degree of photoluminescence polarization in (R/S-3BrMBA)3EuCl6 can be manipulated by the external magnetic field. Particularly, benefiting from the field-generated Zeeman splitting and spin mixing at exciton states, an anomalously positive magneto-photoluminescence was observed at room temperature. This work provides an efficient strategy for constructing both high-performance and pure-red CPL emitters. It also opens the door for chiral rare-earth halides toward chiral optoelectronic and spintronic applications. Chiral organic-inorganic perovskites are promising materials for circularly polarized luminescence. Here the authors present chiral europium halides leading to red circularly polarized luminescence with large dissymmetry factor and strong magneto-chiroptical properties.

Introducing chirality into the metal-halide hybrids has enabled many emerging properties including chiroptical activity, spin-dependent transport, and ferroelectricity. However, most of the chiral metal-halide hybrids to date are non-emissive, and the underlying mechanism remains elusive. Here, we show a new strategy to turn on the circularly polarized luminescence (CPL) in chiral metal-halide hybrids. We demonstrate that alloying Sb3+ into chiral indium-chloride hybrids dramatically increases the photoluminescence quantum yield in two new series of chiral indium-antimony chlorides. These materials exhibit strong CPL signals with tunable energy and a high dissymmetry factor up to 1.5×10-2. Mechanistic studies reveal that the emission originates from the self-trapped excitons centered in 5s2 Sb3+. Moreover, near-ultraviolet pumped white light is demonstrated with a polarization up to 6.0%. Our work demonstrates new strategies towards highly luminescent chiral metal-halide hybrids.

Abstract Chiral zero‐dimensional hybrid metal halides (0D HMHs) could combine excellent optical properties and chirality, making them promising for circularly polarized luminescence (CPL). However, chiral 0D HMHs with efficient CPL have been rarely reported. Here, we propose an efficient strategy to achieve simultaneously high photoluminescence quantum yield (PLQY) and large dissymmetry factor (glum), by integrating achiral and chiral ligands into 0D HMHs. Specifically, three pairs of chiral 0D hybrid indium‐antimony chlorides are synthesized by combing achiral guanidine with three types of chiral methylbenzylammonium‐based derivatives as the organic cations. These chiral 0D HMHs exhibit near‐unity PLQY and large glum values up to around ±1×10−2. The achiral guanidine ligand is not only essential to crystallize these hybrid indium‐antimony chlorides to achieve near‐unity PLQYs, but also greatly enhances the chirality induction from organic ligands to inorganic units in these 0D HMHs. Furthermore, the choice of different chiral ligands can modify the strength of hydrogen bonding interactions in these 0D HMHs, to maximize their glum values. Overall, this study provides a robust way to realize efficient CPL in chiral HMHs, expanding their applications in chiroptical fields.

Finely modulating the structure of the organic cation in metal‐halide semiconductors is a powerful strategy to influence the symmetry and polarity of the hybrid compound as well as its optoelectronic properties. In this study, chiral organic S/R‐hydroxybutylammonium (S/R‐HBA) cations are used to prepare a series of 1D metal‐halide networks. The resulting chiral and polar (S/R‐HBA)2Pb3X8 (X = Br or I) compounds show both second harmonic generation (SHG), circular dichroism (CD), and circularly polarized luminescence (CPL). Contrary to the 1D networks previously prepared from S/R‐2‐hydroxypropyl‐1‐ammonium (S/R‐HP1A) cations, the new compounds show no alteration of their CD signal upon sample flipping, highlighting the suitable orientation of the unique polar axis in both bulk crystal and thin film states. Since no macroscopic effect can interfere with the true chiroptical response when the optical axis of the compound is normal to the incident light beam, (S/R‐HBA)2Pb3Br8 presents a true CPL without sign modulation after flipping or rotating the sample, despite the inherent optical anisotropy in this family of crystalline materials.

Translation of chirality and asymmetry across structural motifs and length scales plays a fundamental role in nature, enabling unique functionalities in contexts ranging from biological systems to synthetic materials. Here, we introduce a structural chirality transfer across the organic–inorganic interface in two-dimensional hybrid perovskites using appropriate chiral organic cations. The preferred molecular configuration of the chiral spacer cations, R-(+)- or S-(−)-1-(1-naphthyl)ethylammonium and their asymmetric hydrogen-bonding interactions with lead bromide-based layers cause symmetry-breaking helical distortions in the inorganic layers, otherwise absent when employing a racemic mixture of organic spacers. First-principles modeling predicts a substantial bulk Rashba-Dresselhaus spin-splitting in the inorganic-derived conduction band with opposite spin textures between R- and S-hybrids due to the broken inversion symmetry and strong spin-orbit coupling. The ability to break symmetry using chirality transfer from one structural unit to another provides a synthetic design paradigm for emergent properties, including Rashba-Dresselhaus spin-polarization for hybrid perovskite spintronics and related applications. Inversion asymmetry imparts rich condensed matter phenomena in inorganic systems, and transmission of chirality across structural motifs is an attractive design strategy to break symmetry. Here, the authors use chiral organic cations to transfer structural chirality to inorganic layers in hybrid perovskites.

… 2D hybrid perovskites with strong spin–orbit coupling (SOC) … chirality of the organic cation, along with the strength of the … gate 2D hybrid perovskites and tune their spin orbit field. The …

Hybrid organic–inorganic perovskites with diverse lattice structures and chemical composition provide an ideal material platform for novel functionalization, including chirality transfer. Chiral perovskites combine organic and inorganic sublattices, therefore encoding the structural asymmetry into the electronic structures and giving rise to the spin-splitting effect. From a structural chemistry perspective, the magnitude of the spin-splitting effect crucially depends on the noncovalent and electrostatic interaction within the chiral perovskite, which induces the local site and long-range bulk inversion symmetry breaking. In this regard, we systematically retrospect the structure–property relationships in chiral perovskite. Insight into the rational design of chiral perovskites based on molecular configuration, dimensionality, and chemical composition along with their effects on spin-splitting manifestation is presented. Lastly, challenges in purposeful material design and further integration into chiral perovskite-based spintronic devices are outlined. With an understanding of fundamental chemistry and physics, we believe that this Perspective will propel the application of multifunctional spintronic devices.

Two-dimensional hybrid organic-inorganic perovskites with chiral spin texture are emergent spin-optoelectronic materials. Despite the wealth of chiro-optical studies on these materials, their charge-to-spin conversion efficiency is unknown. We demonstrate highly efficient electrically driven charge-to-spin conversion in enantiopure chiral perovskites (R/S-MB)2(MA)3Pb4I13 (〈n〉 = 4), where MB is 2-methylbutylamine, MA is methylamine, Pb is lead, and I is iodine. Using scanning photovoltage microscopy, we measured a spin Hall angle θsh of 5% and a spin lifetime of ~75 picoseconds at room temperature in 〈n〉 = 4 chiral perovskites, which is much larger than its racemic counterpart as well as the lower 〈n〉 homologs. In addition to current-induced transverse spin current, the presence of a coexisting out-of-plane spin current confirms that both conventional and collinear spin Hall conductivities exist in these low-dimensional crystals. Editor’s summary Enantiopure two-dimensional perovskites can show high efficiency for charge-to-spin conversion and generate both conventional transverse and unconventional out-of-plane spin currents. Large spin-orbit coupling in Ruddlesden-Popper perovskites enables chirality-induced spin selectivity. Abdelwahab et al. show that four-layer (MB)2(MA)3Pb4I13 (where MB is 2-methylbutylamine and MA is methylamine) has a large spin Hall angle of 5% and a spin lifetime of about 75 picoseconds at room temperature. The two types of current-induced spin currents demonstrate both conventional and collinear spin Hall conductivities. —Phil Szuromi

In the last decade, chirality‐induced spin selectivity (CISS), the spin‐selective electron transport through chiral molecules, has been described in a large range of materials, from insulators to superconductors. Because more experimental studies are desired for the theoretical understanding of the CISS effect, chiral metal‐halide semiconductors may contribute to the field thanks to their chiroptical and spintronic properties. In this regard, this work uses new chiral organic cations S‐HP1A and R‐HP1A (HP1A = 2‐hydroxy‐propyl‐1‐ammonium) to prepare 2D chiral halide perovskites (HPs) which crystallize in the enantiomorphic space groups P43212 and P41212, respectively. The fourfold symmetry induces antiferroelectricity along the stacking axis which, combined to incomplete Rashba‐like splitting in each individual 2D polar layer, results in rare spin textures in the band structure. As revealed by magnetic conductive‐probe atomic force microscopy (AFM) measurements, these materials show CISS effect with partial spin polarization (SP; ±40–45%). This incomplete effect is efficient enough to drive a chiro‐spintronic device as demonstrated by the fabrication of spin valve devices with magnetoresistance (MR) responses up to 250 K. Therefore, these stable lead–bromide HP materials not only represent interesting candidates for spintronic applications but also reveal the importance of polar symmetry‐breaking topology for spin selectivity.

Direct detection of circularly polarized light (CPL) is a challenging task due to limited materials and ambiguous structure–property relationships that lead to low distinguishability of the light helicities. Perovskite ferroelectric semiconductors incorporating chirality provide new opportunities in dealing with this issue. Herein, a pair of 2D chiral perovskite ferroelectrics is reported, which have enhanced CPL detection performance due to interplays among lattice, photon, charge, spin, and orbit. The chirality‐transfer‐induced chiral&polar ferroelectric phase enhances the asymmetric nature of the photoactive sublattice and achieves a switchable self‐powered detection via the bulk photovoltaic effect. The single‐crystal‐based device exhibits a CPL‐sensitive detection performance under 430 nm with an asymmetric factor of 0.20 for left‐ and right‐CPL differentiation, about two times that of the pure chiral counterparts. The enhanced CPL detection performance is ascribed to the Rashba–Dresselhaus effect that originates from the bulk inversion asymmetry and strong spin–orbit coupling, shown with a large Rashba coefficient, which is demonstrated by density functional theory calculation and circularly polarized light excited photoluminescence measurement. These results provide new perspectives on chiral Rashba ferroelectric semiconductors for direct CPL detection and ferroelectrics‐based chiroptics and spintronics.

… significant Rashba effect, supported by an energy splitting of … effect in the heavy elements, we apply spin-orbit coupling (… characteristics by including the spin orbit effect. Notably, they …

The Rashba effect, i.e., the splitting of electronic spin‐polarized bands in the momentum space of a crystal with broken inversion symmetry, has enabled the realization of spin‐orbitronic devices, in which spins are manipulated by spin–orbit coupling. In optics, where the helicity of light polarization represents the spin degree of freedom for spin–momentum coupling, the optical Rashba effect is manifested by the splitting of optical states with opposite chirality in the momentum space. Previous realizations of the optical Rashba effect relied on passive devices determining the surface plasmon or light propagation inside nanostructures, or the directional emission of chiral luminescence when hybridized with light‐emitting media. An active device underpinned by the optical Rashba effect is demonstrated here, in which a monolithic halide perovskite metasurface emits highly directional chiral photoluminescence. An all‐dielectric metasurface design with broken in‐plane inversion symmetry is directly embossed into the high‐refractive‐index, light‐emitting perovskite film, yielding a degree of circular polarization of photoluminescence of 60% at room temperature.

Among various chiral semiconductor materials, chiral two-dimensional (2D)/three-dimensional (3D) composite perovskites (CPs) offer the benefits of strong interface asymmetry and energy transfer between 2D and 3D phases, making the chiral CPs promising for spintronic devices. Therefore, understanding their spintronic properties will be greatly important for expanding their relevant applications. In this work, we synthesized one pair of chiral 2D/3D CP films. Their Rashba effect and spin relaxation process have been investigated by polarization-dependent femtosecond transient absorption spectroscopy. Interestingly, under left- and right-handed circularly polarized light (CPL) excitation, a two-photon emission intensity difference is observed in chiral 2D/3D CP films at 298 K. This work sheds light on the spin-dependent excitonic characteristics of chiral 2D/3D CPs and confirms the feasibility of their application in near-infrared CPL detection.

… a complex vortex-like texture in which the Rashba effect and the Dresselhaus effect coexist. … -of-plane spin component Sz has been directly probed in other chiral and spin–orbitcoupled …

Two-dimensional (2D) chiral perovskites offer a promising magnetic-field-free framework for spin-selective light-matter interactions. Yet, the influence of organic cations on Rashba-related spin effect has not been well comprehended. In this work, we demonstrate that the alloying of achiral and chiral spacers provides an efficient approach to modulating spin-selective phenomena in 2D chiral perovskites. Mixed-spacer films with achiral n-butylammonium spacers in a chiral methylbenzylammonium lattice exhibit enhanced chiroptical activity and spin-dependent optical responses compared the films with achiral or chiral organic cations. Based on the density functional theory and femtosecond circularly polarized transient absorption measurements, it is unveiled that spacer alloying perturbs the local structural environment and modifies Rashba-related band-edge asymmetry, resulting in a larger spin-selective transient response asymmetry and an enhanced optical Stark effect. It is elaborated that achiral-chiral spacer alloying can regulate Rashba-related spin-selective phenomena in 2D chiral perovskites and lead to coherent spin-optoelectronic functioning.

… the intrinsic chirality of the luminescent system, such as chiral … the Rashba-like effect was extensively reported in perovskite … by spin–orbit coupling forming a Zeeman interaction in …

Chirality transfer from organic chiral molecules to lead halides is theorized as the origin of the strong Rashba‐Dresselhaus effect causing large circular dichroism (CD) and circularly polarized luminescence (CPL) in metal halide perovskites (MHPs). Here, a concrete empirical evidence is provided that such strong CD and CPL can occur even in nonchiral 2D Ruddlesden‐Popper perovskites (RPPs) (BA)2(MA)n−1PbnI3n+1 (where MA = CH3NH3 and BA = CH3(CH2)3NH3). The CD and CPL responses occurring at the excitonic transition of the MHPs are strongest (≈100 mdeg and 4.8%, respectively) when a single lead halide octahedral [PbI6]4− layer is repeatedly stacked between two nonchiral molecules BA+ (n = 1). However, they are rapidly quenched as n increases. It is hypothesized that strong Rashba‐Dresselhaus splitting in the 2D RPPs originates the strong CD and CPL signatures. Density functional theory calculations reveal that the large interlayer distortions in the inorganic layers at the organic/inorganic interface give rise to the strong Rashba‐Dresselhaus splitting. A Rashba‐Dresselhaus field of ≈600 and ≈50 mT for n = 1 and 2, respectively, is estimated by magnetic circular dichroism spectroscopy. The studies may have significant impact on designing 2D RPPs with large Rashba‐Dresselhaus effects at room temperature for spintronic applications.

This theoretical Perspective reviews spin-orbit coupling (SOC), including the Rashba effect and Dresselhaus effect, in two-dimensional (2D) semiconductors. We first introduce the origin of the Rashba effect and Dresselhaus effect using the Hamiltonian models; we then summarize 2D Rashba semiconductors predicted by first-principles density functional theory (DFT) calculations, including AB binary monolayers, Janus monolayers, 2D perovskites, and so on. We also review various manipulating techniques of the Rashba effect on 2D semiconductors, such as external electric field, strain engineering, charge doping, interlayer interactions, proximity effect of substrates, and external magnetic field. We then briefly summarize the applications of SOC, including the generation, detection, and manipulation of spin currents in spin Hall effect transistors and spin field effect transistors. Finally, we conclude this Perspective and propose three promising research fields of SOC in low-dimensional semiconductors, including the nonlinear SOC Hamiltonian model, 2D ferroelectric SOC semiconductors, and 1D Rashba model and semiconductors. This theoretical Perspective enriches the fundamental understanding of SOC in 2D semiconductors and will help in the design of new types of spintronic devices in future experiments.

Layered lead halide perovskites have attracted much attention as promising materials for a new generation of optoelectronic devices. To make progress in applications, a full understanding of the basic properties is essential. Here, we study 2D-layered (BA)2PbX4 by using different halide anions (X = I, Br, and Cl) along with quantum confinement. The obtained cell parameter evolution, supported by experimental measurements and theoretical calculations, indicates strong lattice distortions of the metal halide octahedra, breaking the local inversion symmetry in (BA)2PbCl4, which strongly correlates with a pronounced Rashba spin-splitting effect. Optical measurements reveal strong photoluminescence quenching and a drastic reduction in the PL quantum yield in this larger band gap compound. We suggest that these optical results are closely related to the appearance of the Rashba effect due to the existence of a local electric dipole. The results obtained in ab initio calculations showed that the (BA)2PbCl4 possesses electrical polarization of 0.13 μC/cm2 and spin-splitting energy of about 40 meV. Our work establishes that local octahedra distortions induce Rashba spin splitting, which explains why obtaining UV-emitting materials with high PLQY is a big challenge.