铯铅溴、铯铜碘熔体法生长

… The impact of the maximal sample heating temperature on the melt crystallization … CsPbBr 3 melting process and determined the “critical” heating temperature above which the melting …

We show that halide evaporation during melt growth of CsPbBr3 on polycrystalline FTO under partially open conditions drives discrete phase selection between the line compounds of the CsBr–PbBr2 system, producing a sharp CsPbBr3/CsPb2Br5 bilayer instead of compositional grading. In situ optical imaging shows that solidification begins with nucleation and lateral growth of a planar CsPbBr3 single crystal while the melt layer is still thick enough to average over the FTO relief. As the crystal thickens, the residual melt then becomes inhomogeneous and unstable, producing a buried porous layer of faceted CsPb2Br5 grains with a characteristic in-plane spacing of 1–10μm). This morphology is consistent with a faceted Mullins–Sekerka-type instability under a non-conservative evaporative boundary condition. Beneath the single-crystal cap, the first-formed faceted islands are large and become progressively smaller as the advancing front approaches the FTO pyramids, while elevated ambient halide partial pressure suppresses the instability, consistent with diffusion–capillarity selection under decreasing residual melt thickness and steepening local gradients, modified by evaporative flux. Oxygen associated with microvoids or the oxide substrate enables a secondary reaction–diffusion pathway forming Pb–Br–O crystallites without altering the primary length scale. These results identify evaporation as an active control parameter coupling phase equilibria and interfacial stability in volatile halide melts. In the buried, porous bilayer morphology observed here, the secondary phases and porosity reduce the active CsPbBr3 volume and are expected to degrade scintillation through increased trapping, nonradiative recombination, and light scattering.

The CsPbBr3 perovskite material has excellent optoelectronic properties such as large light absorption coefficient, high carrier mobility, long diffusion length, etc., and thus it shows good application prospects in solar cells, photodetectors, high-energy radiation detectors and other fields. Compared with polycrystalline thin films, a single crystal perovskite without grain boundaries has better photoelectric performance, showing photovoltaic potential with higher efficiency and stability. Therefore, the fabrication of CsPbBr3 perovskite single crystals is very important to further explore the potential of single crystal perovskites in various applications. This review systematically summarizes the latest research progress of perovskite CsPbBr3 crystal growth in recent years, and introduces its applications in photodetectors, high-energy radiation detectors, and solar cells. Finally, the challenges and perspectives of perovskite CsPbBr3 crystals are discussed.

All-inorganic perovskite CsPbBr3 has emerged as a promising candidate for stable and cost-effective photovoltaic applications. Pulsed laser deposition (PLD), as a solvent-free, material-efficient, and highly controllable thin-film growth technique, holds tremendous promise for the fabrication of photovoltaic devices. However, during the deposition process, the loose structure, poor thermal conductivity, and microstructural defects of conventional CsPbBr3 targets give rise to the generation of large neutral particles in the ablation plume, deteriorating film quality, and consequently limit device performance. In this work, these bottlenecks are addressed by introducing melt-quenched CsPbBr3 targets to replace conventional powder-pressed ones. Comprehensive analyses reveal that the emission of large neutral particles from the melt-quenched targets and the kinetic energy of species in the ablation plume are both suppressed during deposition, which mitigates the formation of deep-level defects, improves the quality of the thin films, and precludes band misalignment caused by surface dipoles. Ultimately, perovskite solar cells (PSCs) fabricated with the aforementioned target engineering achieve a maximum power conversion efficiency (PCE) of 10.71% and retaining a 93% of initial PCE over 150 days under ambient conditions without any encapsulation. This work presenting a compelling route toward large-area, inline manufacturing and large-scale commercialization for CsPbBr3 PSCs.

… of CsPbBr 3 in melt-grown CsBr host crystals and CsPbBr 3 evaporated films. … The growth direction of 100 is favorable for CsPbBr 3 in Cs 4 PbBr 6 crystal composed thin …

… Except for the melt-grown CsPbBr 3 , the CsPbBr 3 crystals grown in our lab have a higher quality than the reported crystals obtained by the solution method (including AVC and ITC). …

Nuclear radiation detectors serve as fundamental tools in fields of medical imaging, nuclear radiation monitoring, security inspection, and advanced technology development, and their continuous advancement is vital for public safety and propelling progress in nuclear medicine. The performance improvement of the detectors is predominantly dependent on the development of advanced detection materials. Among various nuclear radiation detection materials, halide perovskite CsPbBr 3 single crystals stand out because of the combined capabilities of wide band gap, high resistivity, and high carrier mobility-lifetime product. This article systematically reviews recent progress in the growth of CsPbBr 3 single crystals, the characterization of crystal quality, and the application in nuclear radiation detectors, which provides the qualitative correlation between key physical properties of the single crystal and crucial performance metrics of the detector.

… Results indicated that the CsPbBr 3 single crystals exhibited good thermal stability below … The phase degradation of CsPbBr 3 single crystals along surface defects from the growth …

Melt growth is a process for creating large, bulk single crystals by solidifying a molten material. It combines elements of the Czochralski method, which creates a molten phase, and the Bridgman method, which controls the temperature gradient. Here, we apply two-dimensional (2D) melt growth to synthesize large-scale, single-crystal hybrid organic-inorganic perovskites (HOIPs), enabling substrate-agnostic crystallization with precise thickness control. Our method involves a vapor-liquid-solid process, where the reaction between the pre-deposited inorganic NaxPbBry seeding layer and the organic precursor flux produces the 2D molten phase of HOIPs. This molten phase spreads into a 2D liquid film and allows uniform, large-scale crystallization of ultrathin HOIPs in a substrate-agnostic manner, bypassing requirements for lattice matching. Using this approach, we successfully grow 2D (n = 1) and quasi-2D (n > 1) ferroelectric HOIP films on SiO2/Si wafers at a low thermal budget, enabling direct large-scale device fabrication. Statistical analysis of devices demonstrates reliable ferroelectric switching and uniform electronic performance across the film. Our method holds great potential for other types of HOIPs and heterostructures, paving the way for applications in large-scale on-chip devices.

All‐inorganic perovskite CsPbBr3 crystals have demonstrated considerable promise in γ‐ray and X‐ray detection, owing to their excellent optoelectronic properties. However, the growth of large single crystals (SCs) and the stability of CsPbBr3‐based X‐ray detectors under high‐energy radiation exposure remain unexplored. In this study, a two‐inch CsPbBr3 single‐crystal is grown using the vertical Bridgman (VB) method, and its irradiation resistance in X‐ray detection performance is investigated after exposure to 60Co γ‐ray radiation. Compared with unirradiated samples, the crystals irradiated with a dose of 10 Mrad exhibit a higher trap density (1.59 × 1010 cm−3) and a lower resistivity (8.2 × 107 Ω cm). However, the Bi/CsPbBr3/Au devices with asymmetric electrode structure exhibit an enhanced signal‐to‐noise ratio (14), a stable and low dark current density (7 nA cm−2) with a current drift of 5.8 × 10−15 A cm−1 s−1 V−1, and a high sensitivity of 55722 µC Gyair−1 cm−2 for X‐ray detection at an electric field of 3000 V cm−1. Moreover, the irradiated device remained stable X‐ray response characteristics after 220 days aging. These findings highlight the exceptional defect tolerance and irradiation stability of CsPbBr3 devices for high‐performance radiation detections, offering critical insights for their long‐term deployment in high‐radiation environments.

Wide‐bandgap copper halide semiconductors hold significant potential for next‐generation ultraviolet optoelectronics due to their remarkable photophysical properties. However, defects in polycrystalline films, such as point/interfacial defects and grain boundaries, create pathways for moisture and ion diffusion, thereby compromising device performance and stability. Herein, the capillary epitaxy growth of CsCu2I3 single‐crystal films (SCFs) is demonstrated with a bandgap of 3.68 eV on GaN, by leveraging capillary forces to guide the transport of the molten precursor and using lattice‐matching substrates to achieve crystallographic alignments. This strategy suppresses random nucleation and produces CsCu2I3 SCFs with high crystallinity (rocking curve FWHM = 0.286°). The critical role of lattice matching is further underscored by contrasting the polycrystalline CsCu2I3 or Cs3Cu2I5 films grown on lattice‐mismatched substrates, as well as by the impressive open‐circuit voltage of 1.08 V achieved in the CsCu2I3 SCF/GaN heterojunction. The CsCu2I3 SCF/GaN ultraviolet photodetectors demonstrate nW‐level detection limit (≈2.81 nW) and self‐powered operation, combining the 24 nm narrowband bandwidth with dual‐mode (voltage/current) signal outputs for interference‐resistant detection and communication. The work not only establishes the first route for the epitaxial growth of copper halide SCFs but also paves the way for the hetero‐integration of perovskites onto mature semiconductor platforms for ultraviolet optoelectronics.

… The melting point of pure CsCu 2 I 3 is about 383 C. Accordingly, during growth, the hot … for 8 h and held for 12 h to allow thorough melting. Simultaneously, the cold zone increased from …

Scintillating crystals play a critical role in nuclear energy and radiation detection applications, such as nuclear batteries and radiation dose detectors. Both applications urgently require scintillation crystals with high radioluminescence efficiency. In this work, the Bridgman‐grown 1‐inch Cs3Cu2I5: In single crystals demonstrate the capability of realizing a high‐output‐power nuclear battery and ultrabroad dynamic range radiation dose monitoring. The 1‐inch Cs3Cu2I5: In single crystal has a high photoluminescence quantum yield of 92%, and a high light yield of 32 000 photons MeV−1 under gamma‐ray irradiation. The inch‐sized Cs3Cu2I5: In‐based nuclear battery can achieve a high output power of 1.45 µW, superior to that of most radioluminescent‐type nuclear batteries based on commercial and emerging scintillators. The Cs3Cu2I5: In‐based dosimeter can realize an exceptional dynamic response range of 7.2–46 300 mGy h−1 with a linear correlation coefficient R2 of 0.9999. This work proves the effectiveness of bulk Cs3Cu2I5: In single crystals, acting as the key component of scintillators toward nuclear battery and radiation dose monitor.

Abstract Low-dimensional copper-based halide perovskite single crystals are considered excellent scintillators for indirect X-ray detection, but their potential in direct X-ray detection has not been investigated. Herein, high-quality pure Cs 3 Cu 2 I 5 and Li-doped Cs 3 Cu 2 I 5 :Li single crystals are grown by the Bridgman method. The Li + dopant enhances the photoelectric properties of the Cs 3 Cu 2 I 5 single crystal by extending the carrier life time, improving the carrier mobility from 6.49 to 9.52 cm 2 V -1 s -1 , and increasing the mobility-lifetime (μτ) product from 1.4×10 -4 to 2.9×10 -4 cm 2 V –1 . The sensitive direct X-ray detector with a vertical device configuration of Au/Cs 3 Cu 2 I 5 :Li single crystal/PCBM/Au is fabricated and demonstrated to have a high sensitivity of 831.1 µC Gy air -1 cm -2 and low detection limit of 34.8 nGy air s -1 . Furthermore, the detector shows fast response, negligible baseline current drift and excellent stability upon X-ray illumination.

… We explore the Bridgman growth of both undoped and thallium-doped Li → Cu and Li → Cs substitutional systems with various Li doping levels and assess their impact on scintillation …

… to prevent oxidation of the iodine and copper ions, enabling the … growth methods like Bridgman and Czochralski produce high-quality crystals but require meticulous control of growth …

… growth was conducted in a self-designed vertical two-zone tube furnace by a … CsPbBr 3 single crystal of 8 mm diameter and 60 mm overall length was successfully grown by a facile melt…

Inorganic lead-halide perovskite, cesium lead bromide (CsPbBr3), shows outstanding optoelectronic properties. Both solution- and melt-based methods have been proposed for CsPbBr3 crystal growth. The solution-based growth was done at low-temperature, whereas the melt-based growth was done at high-temperature. However, the comparison of optical, physical, and defect states using these two different growth conditions has been scarcely studied. Here, we have compared the thermal and optical properties of solution-grown and melt-grown single crystals of CsPbBr3. Positron Annihilation Lifetime Spectroscopy (PALS) analysis showed that melt-grown crystal has a relatively smaller number of defects than the chemical synthesis method. In addition, crystals grown using the chemical method showed a higher fluorescence lifetime than melt-grown CsPbBr3.

Single-crystal perovskites demonstrate superior optoelectronic properties when compared to their polycrystalline counterparts, primarily due to their inherently low trap-state density and the absence of grain boundaries. This review comprehensively and...

… CsPbBr3 single crystals mainly include the vertical Bridgman (VB) method and the low-temperature solution-based approaches. As a melt–… , the high-quality CsPbBr3 single crystal was …

Study on the growth of a Li+-doped CsCu2I3 crystal for dual gamma-ray and neutron detection.

Copper‐based halides have emerged as promising scintillator materials for X‐ray imaging due to their favorable photophysical characteristics, such as negligible self‐absorption, high light output, and fast decay. Among these materials, Cs3Cu2I5, a blue emitter, currently delivers the highest scintillation light output under steady‐state X‐rays. However, there is a significant spectral mismatch between its emission band and the spectral responsivity of regular flat‐panel photodiode arrays. In this study, a comprehensive analysis of the physical properties of the CsCu2I3 scintillator is conducted, and its perfect spectral compatibility is discovered, which results in a higher photodiode signal despite its relatively lower light output compared to typical Cs3Cu2I5 scintillators. Furthermore, CsCu2I3 exhibits faster light decay properties, making it especially suitable for Computed Tomography (CT) X‐ray imaging. High‐quality X‐ray cone beam computed tomography (CBCT) imaging is successfully demonstrated using the fast‐decaying CsCu2I3 scintillator screen. Additionally, the flexibility of the scintillator allows for non‐planar imaging, showcasing advantages not available with traditional rigid scintillators. These results not only highlight the significant promise of the CsCu2I3 scintillator but also emphasize the necessity of considering spectral compatibility when designing novel scintillator materials.

The rapid evolution of the Internet of Things has engendered increased requirements for low-cost, self-powered UV photodetectors. Herein, high-performance self-driven UV photodetectors are fabricated by designing asymmetric metal–semiconductor–metal structures on the high-quality large-area CsCu2I3 microwire arrays. The asymmetrical depletion region doubles the photocurrent and response speed compared to the symmetric structure device, leading to a high responsivity of 233 mA/W to 355 nm radiation. Notably, at 0 V bias, the asymmetric device produces an open-circuit voltage of 356 mV and drives to a short-circuit current of 372 pA; meanwhile, the switch ratio (Iph/Idark) reaches up to 103, indicating its excellent potential for detecting weak light. Furthermore, the device maintains stable responses throughout 10000 UV-light switch cycles, with negligible degradation even after 90-day storage in air. Our work establishes that CsCu2I3 is a good candidate for self-powered UV detection and thoroughly demonstrates its potential as a passive device.

Polarization provides a critical yet often overlooked dimension of visual information, enabling enhanced perception of scattering, object orientation, and material anisotropy. However, conventional polarization‐sensitive photodetectors are limited to passive sensing and lack the capability directly encode and retain polarization information in a neuromorphic manner. Here, we report a polarization‐sensitive optoelectronic synaptic device based on lead‐free anisotropic CsCu 2 I 3 single crystals. Benefiting from the intrinsic one‐dimensional chain‐like crystal structure of CsCu 2 I 3 , the device exhibits pronounced polarization‐dependent photoresponses with a high dichroic ratio of up to 2.71, together with broadband UV–Vis sensitivity. More importantly, the polarization state of incident light directly modulates the synaptic response (ΔEPSC), enabling device‐level coupling between polarization‐sensitive photodetection and synaptic‐state modulation. The device successfully emulates essential synaptic behaviors, including pair‐pulse facilitation and spike‐dependent plasticity modulated by pulse width, frequency, intensity, and number. In addition, polarization‐dependent image reconstruction and contrast enhancement are demonstrated based on the experimentally measured polarization‐dependent synaptic responses. This work establishes anisotropic lead‐free halide single crystals as a promising material platform for energy‐efficient and polarization‐aware neuromorphic optoelectronic devices.

Low-dimensional metal halide perovskites possessing a large exciton binding energy have shown great promise in achieving efficient photonic emission required in the fields of lighting sources and d...

… materials to convert X-rays into visible light for detection by … Niu et al. directionally grown CsCu2I3 scintillator films with an area … They believed that the one-dimensional CsCu2I3 crystal …

Lead‐free halide perovskite photodetectors (PDs) based on bismuth (Bi), antimony (Sb), tin (Sn), and copper (Cu) have garnered considerable interest as an alternative to conventional lead‐based perovskite PDs because of their favorable optoelectronic properties, tunable band gaps, and light absorption characteristics. Nevertheless, such PDs face challenges related to charge transport, defect density, stability, and range of detection that hinder their overall photodetection performance. The present review provides insights into various material engineering approaches, including interfacial, morphological, compositional, and heterojunction engineering approaches, aimed at overcoming these challenges. In the case of interfacial engineering, single‐sided, double‐sided, and defect passivation strategies were described in this review. Morphological engineering approaches, including single‐crystal growth techniques, chemical vapor deposition (CVD), nanoporous structures, and space‐confined growth techniques, were also described. Mixed‐halide substitution and metal ion doping are prominent compositional engineering strategies that have been highlighted, along with the optimal tuning of heterojunctions. This review also provided insights into the various photodetection mechanisms of lead‐free halide perovskite PDs, including staggered type‐II band alignment, gradient band alignment, negative photoconductivity, self‐trapped excitons (STEs), and self‐trapped polarons (STPs). Finally, the application of these PDs in imaging and optical communication along with future research perspectives were discussed.

Low‐dimensional metal halides, especially Cu‐based systems, have emerged as promising x‐ray scintillators due to high scintillation efficiency. However, mitigating non‐radiative energy losses remains a critical hurdle to achieving further performance gains. In this work, efficient exciton utilization was achieved in Bridgman‐grown Cs 3 Cu 2 I 5 single crystals by introducing Mn 2 + to modulate exciton relaxation dynamics. The synergistic effect of efficient Mn 2+ ‐centered emission and the energy transfer from STE to Mn 2 + and Mn 2+ ‐Mn 2+ pairs effectively suppresses non‐radiative dissipation, achieving a remarkable light yield of 120 000 photons MeV −1 under x‐ray irradiation. Thanks to ultrabright scintillation yield, the Cs 3 Cu 2 I 5 :Mn single crystals demonstrate a superior spatial resolution of 30 lp mm −1 and a low detection threshold of 91 nGy s −1 , enabling clear resolution of fine features in a 50 µm copper grid. This study clarifies the exciton‐dopant interactions in Mn 2+ ‐activated Cs 3 Cu 2 I 5 scintillators and provides guidance for designing efficient materials for x‐ray imaging.

Cesium Lead Bromide (CsPbBr3) is an upcoming radiation detector semiconductor that has the potential to match the detection properties of Cadmium Zinc Telluride (CZT) and Thallium Bromide (TlBr). This paper...

Inorganic halide perovskite thin-film X-ray detectors have attracted great research interest in recent years due to their high sensitivity, low detection limit, and facile fabrication process. The poor crystal quality of the thin film with uncontrollable thickness and low background voltage during detection limits its practical application. Here, a high-quality CsPbBr3-xIx (x = 0, 1) columnar crystal film is prepared by an improved melt-confined method with a porous anodic aluminum oxide (AAO) template, which stabilizes the disorder perovskite systems of CsPbBr2I by stress. The AAO-CsPbBr3-xIx (x = 0) detectors exhibit high detection accuracy and photoelectric conversion capability with an ultrahigh sensitivity of 32,399.5 μC·Gyair-1·cm-2 at 2142.9 V mm-1 under 20 kVp X-rays and 19,217.4 μC·Gyair-1·cm-2 with a higher background electric field of 6666.7 V mm-1 for AAO-CsPbBr3-xIx (x = 1). Moreover, the AAO-CsPbBr3-xIx (x = 1) film detector acquires a lower detection limit of 7.65 nGy·s-1 and a higher X-ray imaging spatial resolution of 1.6 LP/mm and 8.6 nGy·s-1 and 1.4 LP/mm for AAO-CsPbBr3-xIx (x = 0). The facile, high-quality columnar crystal film devices display great potential for low-energy and low-dose X-ray imaging in flat panel detection applications.

The poor machinability of halide perovskite crystals severely hampered their practical applications. Here a high-throughput growth method is reported for armored perovskite single-crystal fibers (SCFs). The mold-embedded melt growth (MEG) method provides each SCF with a capillary quartz shell, thus guaranteeing their integrality when cutting and polishing. Hundreds of perovskite SCFs, exemplified by CsPbBr3, CsPbCl3, and CsPbBr2.5I0.5, with customized dimensions (inner diameters of 150-1000 µm and length of several centimeters), are grown in one batch, with all the SCFs bearing homogeneity in shape, orientation, and optical/electronic properties. Versatile assembly protocols are proposed to directly integrate the SCFs into arrays. The assembled array detectors demonstrated low-level dark currents (< 1 nA) with negligible drift, low detection limit (< 44.84 nGy s-1), and high sensitivity (61147 µC Gy-1 cm-2). Moreover, the SCFs as isolated pixels are free of signal crosstalk while showing uniform X-ray photocurrents, which is in favor of high spatial resolution X-ray imaging. As both MEG and the assembly of SCFs involve none sophisticated processes limiting the scalable fabrication, the strategy is considered to meet the preconditions of high-throughput productions.

CsPbBr3 nanocrystals (NCs) are successfully prepared by using SrBr2 salt as a growth medium in a melt crystallization process. The obtained CsPbBr3 NCs exhibit a photoluminescence peak of 524 nm with a narrow emission linewidth of 25 nm, which can offer a wide color gamut display. This study can be extended to other alkali metal and alkali earth metal halides and may become a general method for the synthesis of perovskite NCs.

… the deposition rate and promotes grain growth in CsPbBr 3 films/microplates, but … CsPbBr 3 crystals because of its low melting point, which facilitates the growth induction of CsPbBr 3 [24…

Inorganic perovskite CsPbBr3 is a promising material for optoelectronic applications and high-energy radiation detection due to its excellent photophysical properties, high carrier mobility, large carrier diffusion length, and higher stability than organic perovskite materials. Understanding phase transitions at the atomic level is crucial for optimizing its applications. Here, we employ experimental characterizations and molecular dynamics simulations to study the phase transitions in CsPbBr3 as a function of temperature. The simulation results are compared with the experimental results, which include X-ray diffraction (XRD). Our simulations provide new insights into the electronic structure and dynamic behavior of the Cs, Pb, and Br atoms as a function of temperature. We observe distinct phase transitions from monoclinic to cubic and analyze the associated changes in the local environment through atomic density contour maps. Our analysis of the atomic density distributions of the Pb, Br, and Cs atoms provides information about the crystal symmetry as a function of temperature. The tilt and rotation angles of [PbBr6] octahedra are increasing with the temperature increase and are found nonzero above 410 K when the structure is cubic, exhibiting the presence of dynamic tilting. Overall, our findings shed light on the thermal stability and structural dynamics of CsPbBr3, contribute to the fundamental understanding of its phase behavior, and provide a crucial pivot for guiding the design of next-generation optoelectronic and radiation detection devices.

The expanding range of optoelectronic applications of lead-halide perovskites requires their production in diverse forms (single crystals, thinand thick-films or even nanocrystals), motivating the development of diverse materials processing and deposition routes that are specifically suited for these structurally soft, low-melting semiconductors. Pressure-assisted deposition of compact pellets or thick-films are gaining popularity, necessitating studies on the pressure effects on the atomic structure and properties of the resulting material. Herein we report the phase transformation in bulk polycrystalline cesium lead bromide from its threedimensional perovskite phase (γ-CsPbBr3) into the one-dimensional polymorph (δ-CsPbBr3) upon application of hydrostatic pressure (0.35 GPa). δ-CsPbBr3 is characterized by a wide bandgap of 2.9 eV and broadband yellow luminescence at 585 nm (2.1 eV) originating from self-trapped excitons. The formation of δ-CsPbBr3 was confirmed and characterized by Raman spectroscopy, 207Pb and 133Cs solid-state nuclear magnetic resonance, Xray diffraction, absorption spectroscopy, and temperature-dependent and time-resolved photoluminescence spectroscopy. No such phase transition was observed in colloidal CsPbBr3 nanocrystals.

Integrating metallic halide perovskites with established modern semiconductor technology is significant for promoting the development of application-level optoelectronic devices. To realize such devices, exploring the growth dynamics and interfacial carrier dynamics of perovskites deposited on the core materials of semiconductor technology is essential. Herein, we report the incommensurate heteroepitaxy of highly oriented single-crystal cesium lead bromide (CsPbBr3) on c-wurtzite GaN/sapphire substrates with atomically smooth surface and uniform rectangular shape by chemical vapor deposition. The CsPbBr3 microplatelet crystal exhibits green-colored lasing under room temperature and has a structural stability comparable with that grown on van der Waals mica substrates. Time-resolved photoluminescence spectroscopy studies show that the type-II CsPbBr3-GaN heterojunction effectively enhances the separation and extraction of free carriers inside CsPbBr3. These findings provide insights into the fabrication and application-level integrated optoelectronic devices of CsPbBr3 perovskites.

Ion migration in halide perovskite materials usually brings an intractable problem in the working stability of solar cells and photoelectrical detectors. The mechanism of ion migration and its impact on physical properties are still open questions. In this work, the ion migration behavior in solution-grown CsPbBr3 crystals was observed by the hysteresis in current–voltage curves and the temperature dependent reversed current–time measurements. Defect proliferation phenomena (new defects of [VCs]− and [PbBr]2+) originating from ion migration were verified by thermally stimulated current spectroscopy. Our results also give evidence that Cs+ ions also participate in the process of ion migration except the widely considered Br− ions. Furthermore, the photoelectric properties of the CsPbBr3 device were found to be seriously deteriorated after the ion migration. Our work demonstrates the strong correlation between the ion migration and physical properties in halide perovskites.

Inorganic halide perovskites, particularly CsPbBr 3 , have emerged in recent years as promising materials for optoelectronic applications due to their easily tunable bandgap, high charge carrier mobility, and radiation sensing capabilities.

Lead-based halide perovskites have revolutionized optoelectronic technologies, yet their commercialization is hindered by lead toxicity and environmental instability. Zero-dimensional (0D) lead-free halide perovskites, featuring isolated metal halide clusters and tunable...

… In addition, the tiny bubbles are beneficial to the nucleation and growth of nanocrystals during the quenching of the glass melt. With the addition of a small amount of Si 3 N 4 , the glass …

The spatial resolution of X‐ray imaging is often limited by radioluminescence scattering, which is exacerbated in thick scintillators and unpatterned films due to lateral light spreading. Commercial scintillators such as cesium iodide and gadolinium oxysulfide, although hundreds of micrometers thick to ensure efficient X‐ray absorption, still suffer from optical crosstalk, complicated fabrication, and high production costs. To overcome these challenges, we report a novel micropatterned lead‐free green and sustainable 1D Cu‐based perovskite nanocrystals scintillator film. Specifically, polyethylene glycol‐coated CsCu2I3 nanocrystals are used to achieve improved quantum yield and precise thickness control, facilitated by the flexibility and compatibility of polyethylene glycol with the Cu‐based nanocrystals. During polyethylene glycol treatment, zero‐dimensional Cs3Cu2I5 nanocrystals transform into 1D CsCu2I3 nanocrystals, occurring, accompanied by a pronounced redshift in emission, enabling the fabrication of yellow‐emitting scintillator films. Further, photolithographic techniques are used to fabricate patterned substrates with varying pattern sizes and thicknesses, which were subsequently filled with polyethylene glycol‐coated CsCu2I3 nanocrystals via a hot‐press method. The optimized micropatterned scintillator film effectively suppressed optical crosstalk and delivered enhanced spatial resolution under a clinically relevant tube voltage (80 kVp), outperforming unpatterned counterparts. X‐ray imaging at such high voltage conditions has rarely been demonstrated using copper halide materials. This strategy highlights a practical route toward clinically relevant, scalable, and high‐resolution scintillator films for advanced X‐ray imaging.

Copper halide semiconductors are attracting extensive attention due to their nontoxic composition and excellent optoelectronic properties. Most so far are prepared via solution methods; however, grain boundaries and defects existing in those products hinder their further practical applications in solid‐state devices. In this work, CsCu2I3 halides with 1D crystal structure are initially prepared by a vapor phase deposition method. The large Stokes shift coupling with a long photoluminescence decay time (112 ns) suggests the existence of a self‐trapped exciton process in these CsCu2I3 nanowires, responsible for the yellow light emission emerging at 570 nm. UV photodetectors based on individual CsCu2I3 nanowires that are constructed via an etching‐free dry transfer route reveal a responsivity of 122 mA W−1 and rise/decay times of 203/223 ms (310 nm, 5 V bias), comparable to or better than those congeneric UV sensors made of other lead‐free halides. These CsCu2I3 nanowire‐based photodetectors also reveal good stability in the atmosphere (RH = 60–70%, 17 °C), benefitting from their fourfold coordination environment of Cu(I) atoms in the 1D crystal structure. These results imply the technical potential of manufacturing low‐dimensional lead‐free halide semiconductors for next‐generation green optoelectronics.

In recent years, metal halide perovskites have attracted significant interests due to their remarkable optoelectronic and scintillation properties, as well as the benefits of facile and low‐cost processing. All‐inorganic perovskites (AIPs) exhibit superior thermal stability and strong radiation absorption compared with hybrid organic–inorganic perovskites, positioning them as promising candidates for next‐generation scintillators. However, the presence of lead in most perovskite materials poses significant toxicity concerns, driving intensive efforts toward the development of nontoxic, lead‐free AIP alternatives. This review briefly outlines the recent developments of lead‐free AIPs, working principle, different synthesis methods, and scintillation properties associated with self‐trapped exciton (STE). We highlight dopant engineering strategy to favor the formation and efficient radiative recombination of STEs in low‐dimensional AIPs. Finally, we provide the future development direction to pave the way for high‐performance, next‐generation lead‐free AIP scintillators.

… the CsCu2I3 impurity, which can readily form under iodinepoor conditions. It is noteworthy that, when considering the luminescence of intrinsic defects, especially anion vacancies, …

Halide perovskites (HPs) and their derivatives are emerging as a prominent class of materials for ionizing radiation detection. A unique combination of high atomic numbers, efficient luminescence, tunable optoelectronic properties, defect tolerance and low synthesis cost positions them as a promising alternative to traditional scintillators. The review overviews fundamental principles governing perovskite scintillator operation, from radiation absorption to charge carrier generation and recombination. We present a detailed classification of these materials based on structural dimensionality (3D to 0D) and morphology (single crystals (SCs), polycrystalline films, and nanocrystals (NCs)), alongside a discussion of their synthesis methods and the resulting impact on scintillation characteristics. The review highlights compositional and structural engineering techniques, such as activator ion doping, solid-solution formation, and defect passivation. These strategies yield record-breaking performance metrics that rival commercial counterparts, including high light yields (LYs) (>150 000 ph MeV-1), low limits of detection (LoDs) (<10 nGyair s-1), ultrafast responses (<1 ns), and high spatial resolution (>100 lp mm-1). We also discuss the fabrication of composite scintillating screens using polymer and glass matrices, and explore nanostructured systems offering enhanced flexibility, stability, and spatial resolution. Finally, we address key challenges, such as toxicity, scalability, and long-term stability, and outline promising future directions, including the development of multifunctional scintillators, the engineering of materials for photon-counting detectors, the application of emerging paradigms like supramolecular chemistry and nanophotonics, and advancements in data-driven discovery and machine learning technologies.

Inorganic scintillators play a pivotal role in diverse fields like medical imaging, nondestructive detection, homeland security, and high‐energy physics. However, traditional inorganic scintillators encounter challenges such as high fabrication costs and low light yield. Recently, low‐dimensional metal halide scintillators (LDMHS) have witnessed rapid progress, owing to their distinctive crystal structure and superior radioluminescence performance. Herein, an overview of recent advancements and proposed instructive pathways for achieving high‐performance LDMHS is provided. First, the scintillation physical mechanism and emphasis on the essential requirements of scintillators for diverse applications are elucidated. Furthermore, LDMHS are classified according to B‐site cations, and their respective characteristics and recent advancements are introduced. This encompasses the understanding of structure‐property relationships and the routes and rules for optimizing scintillation performance. Finally, the persisting challenges in this burgeoning field and proposed potential research directions for future exploration are discussed.

Cs3Cu2I5 single crystals are regarded as promising next-generation scintillators due to their large Stokes shift and low self-absorption characteristics. However, the cost-effective solution growth method faces critical challenges: the instability of colloidal precursors in solutions and the severe oxidation of Cu+ during crystal growth. This study innovatively introduces yttrium chloride (YCl3) as a dual-functional additive to address both issues simultaneously. The hydrolysis of YCl3 creates a controlled acidic environment, effectively suppressing the oxidation of Cu+; meanwhile, it enhances the stability of colloidal precursors by significantly increasing their surface charge and narrowing the particle size distribution. These synergistic effects enable the rapid growth (approximately 100 h) of near-centimeter-sized Cs3Cu2I5 single crystals with high crystallinity, without the need for inert gas protection. The optimized crystals exhibit exceptional performance: a photoluminescence quantum yield (PLQY) of 93.22% ± 0.47%, a scintillation decay time of 210.04 ns, and a light yield of ~738.14 pe/MeV. This YCl3-mediated growth strategy establishes an efficient approach for the solution-based synthesis of high-quality Cs3Cu2I5 single crystals, holding great significance for advancing high-sensitivity, environment-stable radiation detection applications such as medical diagnostics and nuclear safety monitoring.

… Thus, the addition of H 3 PO 2 favors the rapid growth of centimeter-sized Cs 3 Cu 2 I 5 … crystal growth, facilitating the preparation of large-size and high-performance copper halide …

Cs 3 Cu 2 I 5 is a lead‐free, zero‐dimensional inorganic perovskite noted for its low toxicity, excellent stability, and outstanding optical properties, making it a promising scintillator. Large Cs 3 Cu 2 I 5 single crystals are attainable by solution‐ or melt cooling; however, thermal stress associated with temperature changes often degrades processing yield and crystal quality. Here, we report the growth of large Cs 3 Cu 2 I 5 single crystals (≈3 cm) using a settled temperature and controlled antisolvent diffusion method. The isothermal near‐room‐temperature growth condition eliminates thermal stress and improves mechanical robustness. The as‐grown crystals are readily machined into wafers with high structural integrity, evidenced by a narrow rocking curve FWHM of 20.6″. Cs 3 Cu 2 I 5 single‐crystal wafers used for γ‐ray detection to multiple sources ( 1 3 7 Cs, 2 4 1 Am, 6 0 Co, and 2 2 Na) exhibit outstanding scintillation performance, including a high light yield of 67 500 ph/MeV and an energy resolution of 4.4% ( 1 3 7 Cs). Furthermore, Cs 3 Cu 2 I 5 crystal wafers were utilized as an x‐ray imaging screen, achieving a spatial resolution of 19.3 lp/mm at an MTF of 0.2. The developed technique promotes Cs 3 Cu 2 I 5 crystals toward ready‐for‐use applications.

Since their introduction in the early 20th century, scintillators have become essential components in a wide range of applications, including high-energy physics, medical imaging, cryptography, and nuclear detection. As the...

The advancement of scintillators is of pivotal significance in X‐ray detection and imaging technologies, with widespread applications spanning security inspection, manufacturing quality control, medical diagnostics, and frontier scientific instruments. In recent years, metal halide perovskites and their derivatives have attracted considerable research interest as promising scintillators, attributed to their superior optoelectronic properties. Notably, zero‐dimensional (0D) copper halide Cs3Cu2I5 crystals have emerged as a promising candidate for next‐generation scintillation materials, owing to their near‐unity quantum yield, facile synthesis process, and excellent stability against humidity and X‐ray irradiation. This review first summarizes the crystalline structure of Cs3Cu2I5 and its two intrinsic emission mechanisms. Subsequently, it discusses the progress in X‐ray scintillation imaging performance of Cs3Cu2I5‐based nanocrystals and single crystals. The review then elaborates on the underlying mechanisms of metal ion doping (including Tl+, In+, Mn2+, alkali metals, and alkaline earth metals) in tailoring the optoelectronic properties of Cs3Cu2I5 crystals for scintillation applications. Finally, it highlights the emerging application prospects of Cs3Cu2I5 crystals, such as dual‐energy X‐ray imaging, multi‐energy X‐ray linear‐array detectors, and computed tomography imaging.

Formamidinium-lead-iodide (FAPbI3)-based perovskites with bandgap below 1.55 eV are of interest for photovoltaics in view of their close-to-ideal bandgap. Record-performance FAPbI3-based solar cells have relied on fabrication via the sequential-deposition method; however, these devices exhibit unstable output under illumination due to the difficulty of incorporating cesium cations (stabilizer) in sequentially deposited films. Here we devise a perovskite seeding method that efficiently incorporates cesium and beneficially modulates perovskite crystallization. First, perovskite seed crystals are embedded in the PbI2 film. The perovskite seeds serve as cesium sources and act as nuclei to facilitate crystallization during the formation of perovskite. Perovskite films with perovskite seeding growth exhibit a lowered trap density, and the resulting planar solar cells achieve stabilized efficiency of 21.5% with a high open-circuit voltage of 1.13 V and a fill factor that exceeds 80%. The Cs-containing FAPbI3-based devices show a striking improvement in operational stability and retain 60% of their initial efficiency after 140 h operation under one sun illumination. Formamidinium-lead-iodide-based perovskites have a preferred bandgap below 1.55 eV for solar cell applications but suffer from operational instability. Here, Zhao et al. improve the film quality using cesium-containing seeded growth to show high stabilized efficiency and more than 100 h lifetime under simulated sunlight.

… , we demonstrate the growth of … grow these large (mm-sized) crystals without putting any seed crystal in solution. We conclude that spontaneous nucleation occurs here in crystal growth, …

… We used the vertical Bridgman technique to grow three sets … at 30 kV and 10 mA using a copper target which produced K-alpha … on thallium-doped cesium iodide scintillators. Nuclear …

Copper halide perovskite materials have been studied extensively for use in radiation detection in recent years because of their excellent properties. However, there are few researches on copper bromide perovskite...

High‐performance X‐ray scintillators are essential for advanced imaging technologies in various fields, including security, aerospace, high‐energy physics, and health care. However, the existing scintillation materials in the X‐ray community face significant challenges related to low light yield, long decay time, afterglow, and toxicity. This study reports a novel post‐synthesis surface engineering strategy for copper (Cu)‐doped dicesium silver iodide (Cs2AgI3) using a precisely controlled silver iodide (AgI) treatment to address surface defects, significantly enhancing radiative channels. Density functional theory calculations indicate that AgI treatment passivates the surface defects introduced by Cu⁺ doping, substantially reducing nonradiative recombination centers. Thus, the proposed scintillator achieves an exceptional light yield of over 55 000 photons MeV−1 and a rapid response time of ≈426.4 ns, significantly outperforming the existing commercial scintillators. Furthermore, the scintillator film exhibits an impressive X‐ray imaging resolution (18.5 lp mm−1), enhanced durability, and easy processing, facilitating the scalable production of flexible scintillation screens. These significant advancements underscore the potential of the surface engineering strategy for next‐generation scintillation materials in X‑ray imaging technology.

… synthesis of pure and cesium (Cs) (1, 3, 5, 7 and 10 wt%) doped lead iodide (PbI 2 ) … two layers of iodide ions. It comprises various key applications such as in the development of active …

Halide perovskite semiconductors with extraordinary optoelectronic properties have been fascinatedly studied. Halide perovskite nanocrystals, single crystals, and thin films have been prepared for various fields, such as light emission, light detection, and light harvesting. High‐performance devices rely on high crystal quality determined by the nucleation and crystal growth process. Here, the fundamental understanding of the crystallization process driven by supersaturation of the solution is discussed and the methods for halide perovskite crystals are summarized. Supersaturation determines the proportion and the average Gibbs free energy changes for surface and volume molecular units involved in the spontaneous aggregation, which could be stable in the solution and induce homogeneous nucleation only when the solution exceeds a required minimum critical concentration (Cmin). Crystal growth and heterogeneous nucleation are thermodynamically easier than homogeneous nucleation due to the existent surfaces. Nanocrystals are mainly prepared via the nucleation‐dominated process by rapidly increasing the concentration over Cmin, single crystals are mainly prepared via the growth‐dominated process by keeping the concentration between solubility and Cmin, while thin films are mainly prepared by compromising the nucleation and growth processes to ensure compactness and grain sizes. Typical strategies for preparing these three forms of halide perovskites are also reviewed.

The growth of all-inorganic CsPbBr3 single crystals requires a temperature below 88 °C in order to avoid the orthorhombic to tetragonal phase transition. Here, we report a low-temperature inverse temperature...

… to yield good quality CsPbBr 3 single crystals. Based on results from XRD, EDS, TGA, and DSC, these are similar to those obtained for crystals grown at melting temperatures (>600 C; …

All‐inorganic Cu‐based perovskite CsxCuyIx+y thin films are deposited with vacuum thermal evaporation using CuI and CsI mixed powder with different proportion as evaporation sources. With CuI film as buffer‐layer, the as grown CsxCuyIx+y perovskite films only have CsCu2I3 phase owing to the epitaxy on CuI layer. And the thin film quality and optoelectronic properties of CsCu2I3 are also improved. Then, metal–semiconductor–metal UV detectors based on CsCu2I3 films with Au interdigital electrodes are fabricated and the enhancement of photoresponse performance is investigated in detail. The peak responsivity and specific detectivity of the detector are 49.22 mA W−1 and 2.49 × 1012 cm Hz1/2 W−1, which are 74 and 138 times larger than that of the device without the CuI buffer‐layer, respectively.

All-inorganic perovskite CsCu 2 I 3 thin films have been prepared on Si(100) substrates by pulsed laser deposition technology. And the influence of the substrate temperatures on the …

CsCu2I3 mixed with Cs3Cu2I5 has shown potential applications as white-light-emitting materials, while their growth, structural evolution behaviors, and their impact on photoluminescence of CsCu2I3 nanocrystals (NCs) are still not known. In this work, we investigated the growth and structural evolution of CsCu2I3 nanocrystals with increasing reaction temperature. At low temperature and in the presence of a high dosage of oleic acid and oleylamine, Cs3Cu2I5 nanoparticles, rather than CsCu2I3 NCs, preferred to form in the hot-injection reaction system. Increasing the reaction temperature promoted the formation of CsCu2I3 nanorods. Phase-pure CsCu2I3 nanorods were steadily obtained at 180 °C. Structural evolution from less copper-containing NCs to copper-rich ones in the low-temperature reaction condition is highly related to the coordination of copper ions with OAm. More importantly, accompanying the growth of nanorods and structural evolution from Cu3Cs2I5 to CsCu2I3, the color of photoluminescence emission of NCs changed from blue to nearly white and to yellow, but their photoluminescence quantum yield decreased from 36.00 to 9.86%. The finding in this work would give a view to the structural evolution of copper-containing perovskite-like halides, being helpful for adjusting their photoluminescence in white LEDs.

This study investigates the structural stability and degradation mechanisms of CsCu₂I₃ and Cs₃Cu₂I₅ perovskite nanocrystals (NCs) under laser-induced phase-change conditions. …

High‐resolution scintillation screens with superior light yield play a critical role in many applications. However, conventional single‐crystal scintillators face limitations including challenges in ultra‐thin precision fabrication, hygroscopic nature, and relatively low light yield, which hinder the development and application of high‐resolution X‐ray detectors. In this work, a Cs3Cu2I5‐AAO scintillation screen is fabricated using a negative‐pressure‐assisted low‐temperature solution synthesis method with an anodic aluminum oxide (AAO) template, which achieves ultra‐bright luminescence with a light yield (LY) >70 000 photons/MeV and high spatial resolution (<20 µm). Notably, in addition to the conventional self‐trapped exciton (STE) emission (λSTE = 450 nm), the scintillator exhibits an unprecedented ultrafast blue emission (λBL = 438 nm) with an average lifetime of τavg = 2.279 ns. This phenomenon is reported for the first time in the Cs3Cu2I5 system. Based on reasoned speculation, we propose a surface VI defect‐assisted luminescence mechanism, attributing the fast emission (λBL = 438 nm) to the negative‐pressure heating process during synthesis. Furthermore, the scintillator demonstrates consistent luminescence performance under intense irradiation conditions up to 563.5 mGy/s, indicating notable radiation resistance. These results highlight the promising potential of Cs3Cu2I5‐AAO scintillation screens for applications in semiconductor defect inspection, biological tissue imaging, and 3D printing flaw detection.

Lead halide 2D hybrid perovskites (HP) have emerged as promising materials for photovoltaic and lighting applications. Solvent-free preparations offer greener route, but require congruent melting of halide perovskite for thin films, which has been demonstrated only for monolayered HP (n=1 of the (A) 2 (MA) n-1 Pb n I 3n+1 series) at the quite high temperature T m (T melting ) of 171 °C. Here, we report on the solvent-free preparation (n= 2, 4), thermal behaviour and melt-processed thin films of a series of HP (GABA) 2 (MA) n-1 Pb n I 3n+1 (n= 1, 2, 4; GABA + : 4-ammoniumbutyric acid cation). The n=1 and n=2 HP have an exceptional low congruent T m of 126 °C and 136°C, respectively, and, for n= 1, a very good stability in the molten state. The liquid-solid reaction of molten (GABA) 2 PbI 4 or (GABA) 2 (MA)Pb 2 I 7 with MAPbI 3 in 1/1 (T= 130 °C) or 1/2 (T= 135 °C) ratio leads to pure phases of the n=2 HP and (GABA) 2 (MA) 3 Pb 4 I 11 (n= 4, T m =185°C), respectively. Melt-processed thin films of n=1, n= 2 and n= 4 HP have also been prepared.

Glass, with its unique amorphous properties, offers low thermal conductivity, high catalytic activity, insensitivity to interfacial lattice mismatch, and the absence of grain boundaries. Melt‐quenched organic–inorganic hybrid glass has recently gained significant attention as an emerging material because of its excellent processability and formability. Here, an SbCl3(C25H46ClN)x halide with a low melting point (90 °C) and significant formability is reported. Both the crystalline and glass states of SbCl3(C25H46ClN)x have double broadband emission, and the glass state exhibits negative thermal quenching, which is rare in metal halides. Interestingly, the luminescence properties of SbCl3(C25H46ClN)x glass with different x values differ. This feature is utilized to design multimodal anti‐counterfeiting and information encryption applications. Additionally, The inherent melt processing capability of SbCl3(C25H46ClN)x allows it to be shaped into various forms suitable for practical applications. SbCl3(C25H46ClN)x scintillator screens (diameter 2.2 cm) are successfully prepared by low‐temperature melting, achieving an X‐ray imaging resolution of 18 line pairs per millimeter (18 lp mm−1). This study demonstrates the potential of melt‐processed organic–inorganic hybrid glass SbCl3(C25H46ClN)x in anti‐counterfeiting, information encryption, and X‐ray detection.

A series of monolayered lead halide hybrid perovskites (HO2C(CH2)n-1NH3)2PbX4, named (Cn)2PbX4 (n = 4-6, X = Cl, Br), exhibiting a low congruent melting temperature (Tm) (Tm = 130 °C for (C4)2PbBr4), high stability in the molten state, and whitish type emission, are reported. From the synthesis in the molten state, rare solid solutions of mixed organic cations (Cn1-xCn'x)2PbX4 (n, n' = 4-6; X = Cl, Br; 0 ≤ x ≤1) as well as solid solutions of mixed halides (Cn)2Pb(X1-yX'y)4 (n = 4-6; X, X' = Cl, Br; 0 ≤ y ≤1) have been prepared and characterized (thermal behavior, powder X-ray diffraction (PXRD), photoluminescence properties). The impact of substitutions is significant on the thermal properties, lowering the Tm down to 100 °C for (C4)2Pb(Br0.25Cl0.75)4. The emission properties are slightly tuned in the case of mixed organic cation systems, whereas modifications are more dramatic in the case of mixed halide systems, leading to emission properties through the entire visible region. These results illustrate the great opportunities offered by the congruent melting properties of halide perovskites allowing syntheses in the molten state.

Halide perovskite structures are revolutionizing the design of optoelectronic materials, including solar cells, light‐emitting diodes, and photovoltaics when formed at the quantum scale. Four isolated sub‐nanometer, or picoscale, halide perovskite structures formed inside ≈1.2–1.6 nm single‐walled carbon nanotubes (SWCNTs) by melt insertion from CsPbBr3 and lead‐free CsSnI3 are reported. Three directly relate to the ABX3 perovskite archetype while a fourth is a perovskite‐like lamellar structure with alternating Cs4 and polyhedral Sn4Ix layers. In ≈1.4 nm‐diameter SWCNTs, CsPbBr3 forms Cs3PbIIBr5 nanowires, one ABX3 unit cell in cross section with the Pb2+ oxidation state maintained by ordered Cs+ vacancies. Within ≈1.2 nm‐diameter SWCNTs, CsPbBr3 and CsSnI3 form inorganic‐polymer‐like bilayer structures, one‐fourth of an ABX3 unit cell in cross section with systematically reproduced ABX3 stoichiometry. Producing these smallest halide perovskite structures at their absolute synthetic cross‐sectional limit enables quantum confinement effects with first‐principles calculations demonstrating bandgap widening compared to corresponding bulk structural forms.

Halide perovskites have undergone an impressive development and could be used in a wide range of optoelectronic devices, where some of them are already at the edge of commercialization, e.g., perovskite solar cells. Recently, interest in perovskites in powder form has increased, as for example, they are found to exhibit high stability and allow for easy production of large quantities. Accordingly, also the topic of processing thin and thick films on the basis of perovskite powders is currently gaining momentum. Here, perovskite powder can form the basis for both, typical wet and solvent‐based processing approaches, as well as for dry processes. In this Progress Report, the recent developments of halide perovskites in powder form and of film processing approaches are summarized that are based on them. The advantages and opportunities of the different processing methods are highlighted, but their individual drawbacks and limitations are also discussed. Prospects are also pointed out and possible steps necessary to unlock the full potential of powder‐based processing methods for producing high quality thick and thin perovskite layers in the future are discussed.

Leveraging phase transitions in hybrid metal halides offers broad opportunities for creating programmable, dynamic materials. Here, we report a new family of meltable zero-dimensional Mn2+ hybrid metal halides containing oligo-ethylene glycolammonium cations that exhibit bright green emission and exceptionally low melting points near 55 °C. By varying the length of oligo-ethylene glycol ammonium cations, we tune thermodynamic and optoelectronic properties, linking molecular design with phase stability and optoelectronic properties. Temperature-dependent X-ray diffraction and photoluminescence measurements show that melting leads to a substantial reduction of emission in the molten phase. These results establish oligo-ethylene glycol ammonium cations as an effective strategy for engineering low-melting-point, phase-reconfigurable hybrid metal halides. More broadly, this work demonstrates a pathway toward melt-processable and thermally responsive hybrid semiconductors, with potential applications in sustainable materials processing and adaptive optoelectronic technologies.

Halide perovskites have emerged as a class of most promising and cost-effective semiconductor materials for next generation photoluminescent, electroluminescent and photovoltaic devices. These perovskites have high optical absorption coefficients and exhibit narrow-band bright photoluminescence, in addition to their halide-dependent tuneable bandgaps, low exciton binding energies, and long-range carrier diffusion. These properties make these perovskites superior to classical semiconductors such as silicon. Most importantly, the simple synthesis of perovskites in the form of high quality films, single crystals, nanocrystals and quantum dots has attracted newcomers to develop novel perovskites with unique optoelectronic properties for optical and photovoltaic applications. Here, we comprehensively review recent advances in the synthesis and optoelectronic properties of films, microcrystals, nanocrystals and quantum dots of lead halide and lead-free halide perovskites. Followed by the classification of synthesis, we address the ensemble and single particle properties of perovskites from the viewpoints of the confinement and transport of charge carriers or excitons. Further, we correlate the charge carrier properties of perovskite films, microcrystals, nanocrystals and quantum dots with the crystal structure and size, halide composition, temperature, and pressure. Finally, we illustrate the emerging applications of perovskites to solar cells, LEDs, and lasers, and discuss the ongoing challenges in the field.

A CsPbBr3 single crystal exhibits great potentials in X-ray/gamma-ray spectroscopy and imaging. Here, an inverse temperature crystallization (ITC) method with modified precursor composition is proposed to prepare CsPbBr3 single crystals. The introduction of adduct PbBr2·2DMSO, synthesized by the antisolvent vapor-assisted crystallization method, in the precursor solution gives rise to superior crystallization with a lower impurity concentration and higher resistivity of 6.37 × 109 Ω·cm, as well as a higher hole mobility (50.7 cm2·V–1·s–1). Furthermore, a low dark current of 2.3 nA is obtained at a bias of −100 V based on an as-grown crystal with a thickness of 1 mm, according to the asymmetric Au/CsPbBr3/Sn structure. The resulting asymmetric planar detectors achieve the high peak-to-valley ratio pulse height spectra with an energy resolution of 7.66%, illuminated by an uncollimated 241Am@5.5 MeV α particle. Simultaneously, an energy resolution of 13.5% is realized when irradiated by a 59.5 keV 241Am γ-ray source at room temperature. The thermally stimulated current (TSC) spectra indicate that the density of deep energy-level trap is significantly reduced in the CsPbBr3 crystals grown by PbBr2·2DMSO-modified precursor solution, which is consistent with the high performance in radiation detection.

Metal halide perovskite (MHP) single crystals have shown great potential for high‐performance X‐ray detection due to their excellent carrier transport properties, tunable optical bandgap, and low‐temperature fabrication process. However, 3D perovskite single crystals suffer from severe ion migration, limiting the stability and sensitivity of X‐ray detectors. Herein, a lowing temperature crystallization (LTC) method for liquid‐phase epitaxial growth of 2D (PEA)2PbBr4 single‐crystal (SC) film on 3D CsPbBr3 substrate is demonstratedand a 2D/3D (PEA)2PbBr4/CsPbBr3 SC heterojunction is successfully constructed. The epitaxial (PEA)2PbBr4 layer shows a pronounced passivation effect on CsPbBr3 SC with a low trap density of 2.27 × 1010 cm−3. As such, the prepared 2D/3D heterojunction X‐ray detector achieves a record‐low detectable dose rate of 3.05 nGyair s−1 and high sensitivity of 34496 µC Gyair−1 cm−2 in 120 keV hard X‐ray detection, with a largely suppressed dark current drift of 2.49 × 10−4 nA cm−1 s−1 V−1. In addition, the heterojunction detector exhibits a self‐driven sensitivity of 44 µC Gyair−1 cm−2 due to its built‐in electric field. This work provides a simple strategy to controllable construct 2D/3D MHP SC heterojunction with excellent optoelectronic characteristic, which is conducive to promoting the development of MHP SC X‐ray detectors and other optoelectronic devices.

The concept of quantum-dot-in-perovskite solids pioneered by Ning and co-workers introduces a useful class of solution-processed type I heterostructures for optoelectronics applications. Concurrent searches for solution-processable detectors of ionizing radiation have focused on lead-halide perovskites. As described in this issue of ACS Nano, Cao et al. examined CsPbBr3 nanocrystals imbedded in Cs4PbBr6 as a wider gap host and determined its performance and possibilities as a scintillator for X-ray imaging. In this Perspective, we describe issues and research opportunities on ionizing radiation imaging and spectroscopy based on the CsPbBr3@Cs4PbBr6 composite and other perovskite-dot-in-host combinations in which the dot may be of lower dimensionality than 3, and we explore ionizing radiation detectors using halide perovskites.