有机无机卤化物钙钛矿用于光催化反应，加磁场后提高产率

In recent years, magnetic fields have been widely applied in catalysis to increase the performance of electrocatalysis, photocatalysis, and thermocatalysis through an important noncontact way. This work demonstrated that doping CsPbCl3 halide perovskite nanocrystals with nickel ions (Ni2+) and applying an external magnetic field can significantly enhance the performance of the photocatalytic carbon dioxide reduction reaction (CO2RR). Compared with its counterpart, Ni-doped CsPbCl3 exhibits a sixfold increase in CO2RR efficiency under a 500 mT magnetic field. Insights into the mechanism of this enhancement effect were obtained through photogenerated current density measurements and X-ray magnetic circular dichroism. The results illustrate that the significant enhancement in catalytic performance by the magnetic field is attributed to the synergistic effects of magnetic element doping and the external magnetic field, leading to reduced electron‒hole recombination and extended carrier lifetimes. This study provides an effective strategy for enhancing the efficiency of the photocatalytic CO2RR by manipulating spin-polarized electrons in photocatalytic semiconductors via a noncontact external magnetic field.

Efficient coupling solar energy conversion and N2 fixation by photocatalysis has been shown promising potentials. However, the unsatisfied yield rate of NH3 curbs its forward application. Herein, defective typical perovskite, BaTiO3 , shows remarkable activity under an applied magnetic field for photocatalytic N2 fixation with the NH3 yield rate exceeding 1.90mg/L/h. Through steered surface spin states and oxygen vacancies, the electromagnetic synergistic effect between the internal electric field and an external magnetic field is stimulated. X-ray absorption structure (XAS) spectrum and density functional theory (DFT) calculations reveal the regulation of electronic and magnetic properties through manipulations of oxygen vacancies and inducements of Lorentz force and spin selectivity effect. The electromagnetic synergistic effect suppresses the recombination of photoexcited carriers in semiconducting nanomaterials, which acts synergistically to promote N2 adsorption and activation while facilitating fast charge separation under UV-vis irradiation. Therefore, this work offers a promising alternative route for exploring high-photocatalytic-property N2 fixation materials and shed light on stimulating the development of synergistic effect in photocatalysts.

The magnetic spin degrees of freedom in magnetic materials serve as additional capability to tune materials properties, thereby invoking magneto-optical response. Herein, we report the magneto-optoelectronic properties of a family of lead-free magnetic double perovskites Cs_{2}AgTX_{6} (T = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu; X=Cl, Br, I). This turns out to provide an extremely fertile series, giving rise to potential candidate materials for photovoltaic(PV) applications. In conjunction with high absorption coefficient and high simulated power conversion efficiency for PV applications, few compounds in this series exhibit novel magnetic character useful for spintronic applications. The interaction between magnetism and light can have far-reaching results on the photovoltaic properties as a consequence of the shift in the defect energy levels due to Zeeman effect. This subsequently affects the recombination rate of minority carriers, and hence the photoconversion efficiency. Moreover, the distinct ferromagnetic and anti-ferromagnetic ordering driven by hybridization and super-exchange mechanism can play a significant role to break the time-reversal and/or inversion symmetry. Such a coalescence of magnetism and efficient optoelectronic response has the potential to trigger magnetic/spin anomalous photovoltaic (non-linear Optical) effect in this Cs$_{2}$AgTX$_{6}$ family. These insights can thus channelize the advancement of lead-free double perovskites in magnetic/spin anomalous photovoltaic field as well.

This study explores the bulk crystal growth, structural characterization, and physical property measurements of the cubic double perovskite Ba2CoWO6 (BCWO). In BCWO, Co2+ ions form a face-centred cubic lattice with non-distorted cobalt octahedra. The compound exhibits long-range antiferromagnetic order below TN = 14 K. Magnetization data indicated a slight anisotropy along with a spin-flop transition at 10 kOe, a saturation field of 310 kOe and an ordered moment of 2.17 µB at T = 1.6 K. Heat capacity measurements indicate an effective j = 1/2 ground state configuration, resulting from the combined effects of the crystal electric field and spin-orbit interaction. Surface photovoltage analysis reveals two optical gaps in the UV–Visible region, suggesting potential applications in photocatalysis and photovoltaics. The magnetic and optical properties highlight the significant role of orbital contributions within BCWO, indicating various other potential applications.

Metal halide perovskites (MHPs) exhibit strong spin‐orbit coupling and structural inversion asymmetry, making them ideal for testbeds of Rashba effects and for use in spin‐related optoelectronic and spintronic applications. However, the Rashba band splitting is mainly observed in bulk MHPs so far and is rarely observed in thin films. In this study, a direct observation of Rashba band splitting in MHP thin films at room temperature is reported. By employing a silicone rubber substrate with a high thermal expansion coefficient, the out‐of‐plane tensile strain significantly reduces the activation energy of ion migration in these thin films and leads to a considerable amount of point defects. These point defects disrupt the inversion symmetry and ultimately give rise to the Rashba band splitting. These findings open up new possibilities for manipulating Rashba effects in MHP thin films through device engineering.

The movement of charges through a chiral medium results in a spin-polarized charge current. This phenomenon, known as the chirality-induced spin selectivity (CISS) effect, enables control over spin populations without the need for magnetic components and operates at room temperature. CISS has been discovered in a range of chiral media and most prominently studied in chiral organic molecular species. Chiral hybrid organic-inorganic perovskite semiconductors combine the unique and functional aspects of inorganic semiconductors with chiral molecules. The inorganic component borrows the homochirality of the organic component to yield a unique family of highly tunable chiral semiconductors, where the enantiomeric purity is defined by the organic component. Semiconductors already form the backbone of modern-day technologies. Adding chirality and control over spin through CISS provides new avenues for creative technological development. This review is intended to be an introduction to these unique systems and the demonstrations of CISS and spin control.

Organic-inorganic halide perovskite (OIHP) spintronics has become a promising research field, as it provides a new precisely manipulable degree of freedom. Recently, by utilizing the spin Seebeck effect and inverse spin-Hall effect measurements, we have discovered substantial magnon injection and transport in Pt/OIHP/Y3Fe5O12 nonlocalized structure. In theory, hyperfine interaction (HFI) is considered to have an important role in the magnon transport of OIHP, but there is no clear experimental evidence reported so far. We report increased spin Seebeck coefficient and lengthened magnon diffusion length in deuterated- (D-) OIHP films that have weaker HFI strength compared with protonated- (H-) OIHP. Consequently, D-MAPbBr3 film, as a non-ferromagnetic spacer, achieves long magnon diffusion length at room temperature (close to 120.3 nm). Our finding provides valuable insights into understanding magnon transport in OIHP films and paves the way for the use of OIHPs in multifunctional applications.

Photocatalytic hydrogen evolution (PHE) is attractive for sustainable energy production, yet its efficiency lags photovoltaic conversion mainly due to the step of H‒H bonding for hydrogen generation on photocatalysts. Herein, the spin-enhanced PHE using photocatalysts of chiral perovskites (MBPI) are reported, where the spin orientations of photocarriers are aligned antiparallelly for H‒H bonding via the chiral-induced spin selectivity (CISS) effect. It is observed that the rac-MBPI shows a 3.5-fold enhancement in PHE activity compared with R/S-MBPI under visible light illumination, which is related to the chiral distortions of octahedral units in perovskite structures. Structural distortions lead to the spin polarization of photogenerated carriers in chiral perovskites due to the CISS effect, as revealed by magneto-photocurrent measurements. Compared with the parallel spins in R/S-MBPI, the antiparallel spins in rac-MBPI are more favorable for the coupling of H* radicals, as proven by the electron paramagnetic resonance experiments. The spin-enhanced mechanism for PHE is universal for reduced dimensional (quasi-2D) chiral perovskites, and the H2 yield rate is optimized up to 0.61 mmol g-1 h-1 with an excellent stability over 100 hours.

Organic-inorganic metal hybrids with their tailorable lattice dimensionality and intrinsic spin-splitting properties are interesting material platforms for spintronic applications. While the spin decoherence process is extensively studied in lead- and tin-based hybrids, these systems generally show short spin decoherence lifetimes, and their correlation with the lattice framework is still not well-understood. Herein, we synthesized magnetic manganese hybrid single crystals of (4-fluorobenzylamine)2MnCl4, ((R)-3-fluoropyrrolidinium)MnCl3, and (pyrrolidinium)2MnCl4, which represent a change in lattice dimensionality from 2D and 1D to 0D, and studied their spin decoherence processes using continuous-wave electron spin resonance spectroscopy. All manganese hybrids exhibit nanosecond-scale spin decoherence time τ2 dominated by the symmetry-directed spin exchange interaction strengths of Mn2+-Mn2+ pairs, which is much longer than lead- and tin-based metal hybrids. In contrast to the similar temperature variation laws of τ2 in 2D and 0D structures, which first increase and gradually drop afterward, the 1D structure presents a monotonous rise of τ2 with the temperatures, indicating the strong correlation of spin decoherence with the lattice rigidity of the inorganic framework. This is also rationalized on the basis that the spin decoherence is governed by the competitive contributions from motional narrowing (prolonging the τ2) and electron-phonon coupling interaction (shortening the τ2), both of which are thermally activated, with the difference that the former is more pronounced in rigid crystalline lattices.

The solar cell and light-emitting device research community is currently focusing on investigating two-dimensional (2D) hybrid perovskite materials owing to their remarkable stability and intriguing optoelectronic characteristics, which hold significant promise for various applications. In general, the introduction of chirality in hybrid perovskites arises from symmetry breaking within their inorganic frameworks. Nevertheless, despite this understanding, the specific factors driving the observed increase in splitting remain obscure due to a lack of comprehensive investigations. Our research delves into the electronic properties of 2D layered hybrid perovskites, considering their behavior with and without spin-orbit coupling. We specifically focus on effect of Rashba splitting and the impact of electronic structure variation across a range of chiral perovskites by introducing chiral organic cations with differing degrees of π-conjugation, resulting in significant changes in spin-splitting magnitude. Systematic first principles investigations confirm that the distortion of the cage and d-spacing of chiral perovskites are crucial design parameters for achieving strong spin-splitting in 2D layered perovskites. Furthermore, our investigation reveals that these systems exhibit remarkable absorption capabilities in the visible light spectrum, as demonstrated by their computed optoelectronic characteristics. The chiral perovskites described in this study, which exhibit substantial spin-splitting, present a distinctive prototype with potential implications for spintronics and photovoltaics.

Chirality‐induced spin selectivity observed in chiral 2D organic–inorganic hybrid perovskite holds promise to achieve spin‐dependent electrochemistry. However, conventional chiral 2D perovskites suffer from low conductivity and hygroscopicity, limiting electrochemical performance and operational stability. Here, a cutting‐edge material design is introduced to develop a stable and efficient chiral perovskite‐based spin polarizer by employing fluorinated chiral cation. The fluorination approach effectively promotes the charge carrier transport along the out‐of‐plane direction by mitigating the dielectric confinement effect within the multi‐quantum well‐structured 2D perovskite. Integrating the fluorinated cation incorporated spin polarizer with BiVO4 photoanode considerably boosts the photocurrent density while reducing overpotential through a spin‐dependent oxygen evolution reaction. Furthermore, the hydrophobic nature of fluorine in spin polarizer endows operational stability to the photoanode, extending the durability by 280% as compared to the device with non‐fluorinated spin polarizer.

Fundamental understanding on the spin transport properties of semiconducting organic-inorganic hybrid perovskites (OIHP) is of great importance for advancing their applications for spin-optoelectronic devices. Herein, the study of spin-pumping induced inverse spin Hall effect in Ni80Fe20(Py)/CH3NH3PbCl3-xIx/Pt trilayer with different OIHP spacer thicknesses concludes the spin diffusion length in CH3NH3PbCl3-xIx as large as 61  7 nm at room temperature. In addition, spin-valves with a structure of Ni80Fe20(Py)/CH3NH3PbCl3-xIx/AlOx/Co was fabricated as well. Using ~160 nm thick CH3NH3PbCl3-xIx spacer, the present spin valve exhibits a positive magnetoresistance (MR) of 0.57% at 10 K. Thus, the present spin related results demonstrate that electrical spin-polarized carrier injection, transport, and detection, which are essential in spintronic devices, can be successfully established in OIHP films. The outstanding spin transport in the present CH3NH3PbCl3-xIx should be owing to its highly out-of-plane oriented crystalline texture and Rashba spin splitting at domain boundaries between crystallographic orientations. These results demonstrate OIHP as very attractive materials for spintronics.

Rashba spin-splitting in hybrid organic-inorganic perovskites (HOIPs) holds great promise for spintronic applications. However, strategies for controlling Rashba spin-splitting in these materials remain underexplored. Here, we find organic cation dipole moments play a pivotal role in modulating Rashba effects. By comparing p-FPEA2PbI4 and PEA2PbI4, we demonstrate that larger dipole moments amplify lattice distortion and local symmetry breaking, as confirmed by second-harmonic generation. This structural asymmetry doubles the Rashba spin-splitting energy, quantified through circular photogalvanic effect and circularly polarized light excited photoluminescence. Circular dichroism and magnetic circular dichroism reveal a Rashba-induced effective magnetic field, while spin pumping resolves a ~50% higher Rashba coefficient in p-FPEA2PbI4. These results establish a direct correlation between dipole strength and spin splitting in 2D HOIPs, a trend that extends to quasi-2D and 3D HOIPs. Our work shows dipole engineering as a universal design rule for tailoring Rashba effects in HOIPs, paving the way for high-efficiency spin-based optoelectronics and quantum devices.

The two-dimensional (2D) Ruddlesden−Popper organic-inorganic halide perovskites such as (2D)-phenethylammonium lead iodide (2D-PEPI) have layered structure that resembles multiple quantum wells (MQW). The heavy atoms in 2D-PEPI contribute a large spin-orbit coupling that influences the electronic band structure. Upon breaking the inversion symmetry, a spin splitting (‘Rashba splitting’) occurs in the electronic bands. We have studied the spin splitting in 2D-PEPI single crystals using the circular photogalvanic effect (CPGE). We confirm the existence of Rashba splitting at the electronic band extrema of 35±10 meV, and identify the main inversion symmetry breaking direction perpendicular to the MQW planes. The CPGE action spectrum above the bandgap reveals spin-polarized photocurrent generated by ultrafast relaxation of excited photocarriers separated in momentum space. Whereas the helicity dependent photocurrent with below-gap excitation is due to spin-galvanic effect of the ionized spin-polarized excitons, where spin polarization occurs in the spin-split bands due to asymmetric spin-flip. Hybrid organic-inorganic perovskites (HOIP) have high potential for spintronics applications. Using the circular photogalvanic effect the authors demonstrate the existence of Rashba-splitting in the continuum bands of a 2D layered HOIP that results from inversion symmetry breaking along the growth direction.

No abstract available

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.

No abstract available

Chiral hybrid perovskites have aroused great interest due to their unique versatile properties. However, designing chiral perovskites with narrow bandgaps is challenging, with their electronic properties such as the Rashba-Dresselhaus effect and piezoelectricity remaining unclear. Herein, single crystals of zero-dimensional (0D) tellurium-based chiral hybrid perovskite, (R-/S-α-PEA)2TeI6 and (R-/S-α-PEA)2TeBr6 (PEA = phenylethylammonium), with sizes of over 5 mm are grown by seed-crystal-assisted solution-temperature-lowering. The optical bandgaps are about 1.60 and 2.18 eV for the iodide and bromide analogues, respectively, which are the lowest among various chiral lead-free hybrid perovskites with the same halide ions in the X-site to the best of our knowledge. First-principles calculations reveal that (R-/S-α-PEA)2TeBr6 shows a larger Rashba-Dresselhaus spin-splitting than (R-/S-α-PEA)2TeI6, probably thanks to the greater distortion of [TeBr6] octahedra. Moreover, the piezoelectric coefficients d33 of (R-/S-α-PEA)2TeI6 and (R-/S-α-PEA)2TeBr6 are about 2.6 and 1.8 pC N-1, respectively. This work deepens the understanding of physical properties of 0D tellurium-based chiral perovskites with potential multifunctionality, including spintronic and piezoelectric performances.

Methylammonium lead iodide perovskite (MAPbI3) exhibits long charge carrier lifetimes that are linked to its high efficiency in solar cells. Yet, the mechanisms governing these unusual carrier dynamics are not completely understood. A leading hypothesis—disproved in this work—is that a large, static bulk Rashba effect slows down carrier recombination. Here, using second harmonic generation rotational anisotropy measurements on MAPbI3 crystals, we demonstrate that the bulk structure of tetragonal MAPbI3 is centrosymmetric with I4/mcm space group. Our calculations show that a significant Rashba splitting in the bandstructure requires a non-centrosymmetric lead iodide framework, and that incorrect structural relaxations are responsible for the previously predicted large Rashba effect. The small Rashba splitting allows us to compute effective masses in excellent agreement with experiment. Our findings rule out the presence of a large static Rashba effect in bulk MAPbI3, and our measurements find no evidence of dynamic Rashba effects.The high performance of hybrid perovskite solar cells has attracted significant attention but the nature of the underlying mechanisms remains unclear. Frohna et al. show methylammonium lead iodide perovskite is centrosymmetric, invalidating previous predictions of a large bulk Rashba effect.

No abstract available

Molecular ferroelectrics have attracted extensive research interest due to their ferroelectric and piezoelectric properties, along with their tunable band structures, making them promising candidates for piezo-photocatalysis. However, the role of spontaneous polarization and piezoelectric fields in charge transfer remains insufficiently understood. In this study, we explored the ferroelectric organic-inorganic perovskite (4,4-difluorocyclohexylammonium)2PbI4 ((4,4-DFPD)2PbI4) as a piezo-photocatalyst in the HI splitting process for hydrogen production. Under combined ultrasonic and visible light irradiation, the hydrogen production rate of (4,4-DFPD)2PbI4 reached 1185.1 µmol·h-1·g-1, 1.95 times higher than under visible light alone and 12.1 times greater than that of the conventional MAPbI3 perovskite catalyst. Experimental and theoretical analyses reveal that the combination of light and pressure synergistically enhances charge separation and boosts catalytic efficiency, driven by built-in electric fields from spontaneous polarization, piezoelectric fields, and photoexcitation. This work provides valuable insights for the design of novel molecular ferroelectric catalysts with high efficiency for photocatalytic hydrogen evolution.

The co-existence of superior photocatalytic property and strong spin-orbit-coupling (due to structural inversion asymmetry) in two-dimensional polar MoSSe intensifies the possibility of spin-dependent photo-excited charge transfer for efficient catalysis under...

No abstract available

Organolead trihalide perovskites have attracted substantial interest regarding applications in charge-based photovoltaic and optoelectronic devices, because of their low processing costs and remarkable light absorption and charge transport properties. Although spin is an intrinsic quantum descriptor of a particle and spintronics have been a central research theme in condensed matter physics, few studies have explored the spin degree of freedom in the emerging hybrid perovskites. Here, we report the characterization of a spin valve that uses hybrid perovskite films as the spin-transporting medium between two ferromagnetic electrodes. Because of the light-responsive nature of the hybrid perovskite, a high magnetoresistance of 97% and a large spin diffusion length of 81 nm were achieved at 10 K under light illumination in polycrystalline films. Furthermore, by using thin perovskite single crystals, we discovered that the spin diffusion length was able to reach 1 μm at low temperatures. Our results indicate that the spin relaxation is not significant as previously expected in such lead-containing materials and demonstrate the potential of low-temperature-processed hybrid perovskites as new active materials in spintronic devices.

Chiral molecules in Pb-halide 2D-layered films achieve up to 86% spin-polarized transport, enabling novel spintronic applications. Chiral-induced spin selectivity (CISS) occurs when the chirality of the transporting medium selects one of the two spin ½ states to transport through the media while blocking the other. Monolayers of chiral organic molecules demonstrate CISS but are limited in their efficiency and utility by the requirement of a monolayer to preserve the spin selectivity. We demonstrate CISS in a system that integrates an inorganic framework with a chiral organic sublattice inducing chirality to the hybrid system. Using magnetic conductive-probe atomic force microscopy, we find that oriented chiral 2D-layered Pb-iodide organic/inorganic hybrid perovskite systems exhibit CISS. Electron transport through the perovskite films depends on the magnetization of the probe tip and the handedness of the chiral molecule. The films achieve a highest spin-polarization transport of up to 86%. Magnetoresistance studies in modified spin-valve devices having only one ferromagnet electrode confirm the occurrence of spin-dependent charge transport through the organic/inorganic layers.

Hybrid organic-inorganic perovskites (HOIPs) with chiral organic ligands exhibit highly spin-dependent transport and strong natural optical activity (NOA). Here we show that these remarkable features can be traced to a chirality-induced spin-orbit coupling (SOC), Hso = ατkzσz, which connects the carrier's spin (σz), its wave vector (kz), and the material's helicity (τ) along the screw direction with strength α controlled by the geometry of the organic ligands. This SOC leads to a macroscopic spin polarization in the presence of an electrical current and is responsible for the observed spin-selective transport. NOA originates from a coupling between the exciton's center-of-mass wave vector Kz and its circular polarization jzex, Hso' = α'τKzjzex, contributed jointly from the electron's and the hole's SOCs in an exciton. Our model provides a roadmap to achieve a strong and tunable chirality in HOIPs for novel applications utilizing carrier spin and photon polarization.

No abstract available

Chirality-induced spin selectivity (CISS) in non-centrosymmetric chiral structures creates a new platform for spintronics in organic-inorganic hybrid systems. Chiral Pb(Sn)-I hybrid perovskites exhibit outstanding spin-dependent charge transport performance, but the nontoxic lead-free hybrid materials with high stability are still greatly desired for spin-filtering applications. Here, we synthesize chiral hybrid copper halides ( R/S -MBA) 2 Cu X 4 (MBA = methylbenzylammonium; X = Cl, Br) with characteristic 0D Cu X 4 tetrahedral structural motifs, combining the low toxicity of Cu 2+ and air stability of halide ions (Cl - and Br - ). (MBA) 2 CuBr 4 experiences a phase transition from orthorhombic to monoclinic after spin-coating and annealing during the thin film preparation, while (MBA) 2 CuCl 4 keeps invariant monoclinic structure. Despite similar structural and electronic features, ( R/S -MBA) 2 CuBr 4 shows much smaller chiroptical activity than the chloride counterpart. Magnetic-conductive atomic force microscopy measurements display a typical spin-filtering transport property with high efficiency up to 90% for both copper halides. Our work expands spin-polarized charge transport in eco-friendly and stable metal-organic halides, which is promising to be applied in spintronics based on transition-metal hybrid systems.

The hybrid organic-inorganic halide perovskite (HOIP), for example, MAPbBr3, exhibits extended spin lifetime and apparent spin lifetime anisotropy in experiments. The underlying mechanisms of these phenomena remain illusive. By utilizing our first-principles density-matrix dynamics approach with quantum scatterings including electron-phonon and electron-electron interactions and self-consistent spin-orbit coupling, we present temperature- and magnetic field-dependent spin lifetimes in hybrid perovskites, in agreement with experimental observations. For centrosymmetric hybrid perovskite MAPbBr3, the experimentally observed spin lifetime anisotropy is mainly attributed to the dynamic Rashba effect arising from the interaction between organic and inorganic components and the rotation of the organic cation. For noncentrosymmetric perovskites, such as MPSnBr3, we found persistent spin helix texture at the conduction band minimum, which significantly enhances the spin lifetime anisotropy. Our study provides theoretical insight into spin dynamics in HOIP and strategies for controlling and optimizing spin transport.

The photocatalytic conversion of CO2 into the renewable fuels is a promising strategy to address energy and environmental challenges, however, its limited application is mainly attributed to the inefficient charge separation and lack of active sites in conventional catalysts. Here, a spin‐polarization strategy using Co2⁺ doping in lead‐free perovskite Cs3Bi2Br9 (CBB) synergized with an external magnetic field (MF), is reported to achieve highly efficient CO2 reduction. The optimized Co‐doped CBB (0.2CBB) exhibited a 2.6‐fold enhancement in CO production rate (35.04 µmolg−1h−1) compared to the pristine CBB, with further improvement to 86.56 µmolg−1h−1 under 200 mT MF. Advanced characterizations together with the density functional theory calculations further revealed that the Co doping introduces spin‐polarized electrons, suppresses charge recombination, and elongates the carrier lifetime (6.68 ns vs 5.20 ns in CBB). The Zeeman effect under MF activates the additional spin‐polarized carriers, while the Co sites lower the energy barrier for *COOH intermediate formation (ΔG = −0.59 vs −0.38 eV in CBB), as confirmed by the in situ FT‐IR and Gibbs free energy analysis. This work pioneers the integration of spin manipulation and MF‐assisted catalysis in perovskites, offering a novel pathway for the design of high‐performance photocatalytic systems.

"Spin" has been recently reported as an important degree of electronic freedom to improve the performance of electrocatalysts and photocatalysts. This work demonstrates the manipulations of spin-polarized electrons in CsPbBr3 halide perovskite nanoplates (NPLs) to boost the photocatalytic CO2 reduction reaction (CO2RR) efficiencies by doping manganese cations (Mn2+) and applying an external magnetic field. Mn-doped CsPbBr3 (Mn-CsPbBr3) NPLs exhibit an outstanding photocatalytic CO2RR compared to pristine CsPbBr3 NPLs due to creating spin-polarized electrons after Mn doping. Notably, the photocatalytic CO2RR of Mn-CsPbBr3 NPLs is significantly enhanced by applying an external magnetic field. Mn-CsPbBr3 NPLs exhibit 5.7 times improved performance of photocatalytic CO2RR under a magnetic field of 300 mT with a permanent magnet compared to pristine CsPbBr3 NPLs. The corresponding mechanism is systematically investigated by magnetic circular dichroism spectroscopy, ultrafast transient absorption spectroscopy, and density functional theory simulation. The origin of enhanced photocatalytic CO2RR efficiencies of Mn-CsPbBr3 NPLs is due to the increased number of spin-polarized photoexcited carriers by synergistic doping of the magnetic elements and applying a magnetic field, resulting in prolonged carrier lifetime and suppressed charge recombination. Our result shows that manipulating spin-polarized electrons in photocatalytic semiconductors provides an effective strategy to boost photocatalytic CO2RR efficiencies.

The construction of chiral materials has always been a research hotspot in the field of inorganic chiral nanomaterials. By introducing chiral destructive agents, materials are endowed with chiral nanostructures, its unique chiral-induced spin selectivity (CISS) can be applied in the field of photocatalysis. Au nanoparticles (Au NPs) are a typical photosensitizer capable of producing surface plasmon resonance (SPR) effects, producing CO and CH4 in photocatalytic CO2 reduction. However, the activity of Au NPs is low, resulting in a low reaction yield. Therefore, we investigated the photocatalytic CO2 reduction performance of the Au NPS deposited inorganic chiral bismuth bromide oxide nanomaterial photocatalyst (D-BiOBr/Au). It is worth noting that D-BiOBr/Au chiral materials enhance spin-polarized electrons due to SPR and CISS effect, and their photocatalytic CO2 reduction performance is significantly better than D-BiOBr and original BiOBr without SPR and CISS effect. The CO yield of D-BiOBr/Au0.3 % is 24.39 μmol/g h-1, which is 2.02 times of D-BiOBr and 2.43 times of BiOBr, respectively. In the Mc-AFM test, the tunnel current of D-BiOBr/Au0.3 % was the strongest, showing stronger spin-polarized electrons. The mechanism of photocatalytic CO2 reduction was further studied by FDTD simulation. The reason for the improved photocatalytic CO2 reduction efficiency of D-BiOBr/Au is the increase of spin-polarized electrons due to the SPR effect, thus prolonging the carrier lifetime and promoting spin-polarized electron-hole separation. The results show that enhancing spin-polarized electrons through SPR effect is an effective strategy to improve photocatalyzed CO2 reduction in photocatalyzed semiconductors.