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Copyright of Rare Metals is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The electronic and optical properties of RbPbBr3/RbPbBr2Cl, RbPbBr3/RbSnBr3 and RbSnBr3/RbSnBr2Cl heterostructures were studied using first-principle approach. The calculations show that the energy gaps are equal to 1.54, 0.96 and 0.67 eV (the energies are in the infrared range), respectively. Also, unlike the strong metallic property of RbSnBr3/RbSnBr2Cl, in the band structures of RbPbBr3/RbPbBr2Cl and RbPbBr3/RbSnBr3, the minimum of conduction bands is tangential to the Fermi level. Also, the density of states (DOS) diagrams around the Fermi level have negligible amplitude, so, the density of charge carriers is low and thereby both heterostructures (similar to graphene) can be suitable for electronic applications. The effective mass calculations show; me* & mh* < 0.5 me, therefore, in all three cases, charge carriers have significant mobilities and these structures are suitable for photovoltaic and optoelectronic applications. Also, partial density of states (PDOS) diagrams show that the charge carriers are concentrated in certain layers, therefore, in all three heterostructures, the two-dimensional electron gas is formed. By plotting the diagrams of changes in the length of the anion–cation–anion bond perpendicular to the junction, it can be seen that the ferroelectric-like property appears in these structures. The optical calculations show, for all cases, the refractive index in the range of (0.0–5.0 eV) has a value of about 1.6, with peaks as large as 1.87. In this range the reflectivity varies between 0.06 and 0.12. Finally, we found that the RbPbBr3/RbSnBr3 structure has two visible absorption peaks at 1.96 and 3.09 eV, while the heterostructures of RbPbBr3/RbPbBr2Cl and RbSnBr3/RbSnBr2Cl, each have one visible peak that are located at 2.78 and 2.11 eV respectively. [ABSTRACT FROM AUTHOR]

Encapsulating Cs4PbBr6 quantum dots in silicon nano-sheets not only stabilizes the halide perovskite, but also takes advantage of the nano-sheet for a compatible integration with the traditional silicon semiconductor. Here, we report the preparation of un-passivated Cs4PbBr6 ellipsoidal nanocrystals and pseudo-spherical quantum dots in silicon nano-sheets and their enhanced photoluminescence (PL). For a sample with low concentrations of quantum dots in silicon nano-sheets, the emission from Cs4PbBr6 pseudo-spherical quantum dots is quenched and is dominated with Pb2+ ion/silicene emission, which is very stable during the whole measurement period. For a high concentration of Cs4PbBr6 ellipsoidal nanocrystals in silicon nano-sheets, we have observed Förster resonance energy transfer with up to 87% efficiency through the oscillation of two PL peaks when UV excitation switches between on and off, using recorded video and PL lifetime measurements. In an area of a non-uniform sample containing both ellipsoidal nanocrystals and pseudo-spherical quantum dots, where Pb2+ ion/silicene emissions, broadband emissions from quantum dots, and bandgap edge emissions (515 nm) appear, the 515 nm peak intensity increases five times over 30 min of UV excitation, probably due to a photon recycling effect. This irradiated sample has been stable for one year of ambient storage. Cs4PbBr6 quantum dots encapsulated in silicon nano-sheets can lead to applications of halide perovskite light emitting diodes (PeLEDs) and integration with traditional semiconductor materials. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of High Pressure Physics is the property of Chinese Journal of High Pressure Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The function of photodetectors is to convert optical signals into current or voltage output. Polarization‐sensitive perovskite photodetectors have attracted significant interest because of their potential applications in imaging and remote sensing technologies. This study provides an overview of the advancements in research on halide perovskite photodetectors, particularly focusing on their capability for linear polarization‐sensitive detection. First, there is a brief description of the background and strengths of linear polarization‐sensitive photodetectors. Then, the core parameters of linear polarization‐sensitive photodetectors are introduced briefly. Third, according to the classification of active layer materials, linear polarization‐sensitive photodetectors are divided into 3D perovskites and low‐dimensional perovskites. The research on linear polarization‐sensitive perovskite detectors are reviewed. Finally, the developments and challenges faced by linear polarization‐sensitive perovskite photodetectors are analyzed. [ABSTRACT FROM AUTHOR]

Allylic C−H amination has emerged as a powerful tool to construct allylamines, common motifs in molecular therapeutics. Such reaction implies an oxidative path for C−H activation but furnishes reductive amines, inferring mild oxidants’ inactivity for C−H oxidation but strong oxidants’ detriment to products. Herein we report a heterogeneous catalytic approach that manipulates halogen‐vacancies of perovskite photocatalyst and exploits halogenated‐solvents (i.e. CH2Cl2, CH2Br2) as mild oxidants for selective C−H allyl amination with 19,376 turnovers. CsPbBr3 nanocrystals induce cooperative hydrogen‐atom‐transfer (HAT, C−H oxidation, and halogen‐vacancy CsPbBr3−x formation) and halogen‐atom‐transfer (XAT, CsPbBr3−x‐induced solvent reduction) under a radical chain mechanism. Terminal/internal olefins are amenable to forge aromatic/aliphatic, cyclic/acyclic, secondary/tertiary allylamines (70 examples), including drugs or their derivatives. [ABSTRACT FROM AUTHOR]

In this study, self-assembled halide perovskite quantum wire bundles (QWBs)/quantum dots (QDs) are fabricated using a room temperature-based formation method. The one-dimensional (1D) perovskite-based QWB structures incorporate zero-dimensional QDs within a composite quantum structure. Transmission electron microscopy reveals that quantum wires with diameters ranging from tens of nanometers to approximately 200 nm maintain a single-crystal atomic arrangement in a bundle form. Conversely, QDs are uniformly distributed within the single-phase wire and appear as black dots < 10 nm. Photoluminescence analysis identifies the multiband characteristics of the emissions. The 420–440 nm band is attributed to 1D QWB, whereas the peak appearing in the 530–550 nm range corresponds to lead halide PbBr2 QDs. Thus, the proposed self-assembled 1D QWB/QD composite structure exhibits novel multiband physical properties in the 420–440 and 530–550 nm bands; it offers new opportunities for designing materials with potential applications in optoelectronic devices. [ABSTRACT FROM AUTHOR]

In recent years, the power conversion efficiency of perovskite solar cells has increased rapidly. Perovskites can be prepared using simple and cost-effective solution methods. However, the perovskite films obtained are usually polycrystalline and contain numerous defects. Passivation of these defects is crucial for enhancing the performance of solar cells. Here, we report the use of propylamine hydroiodide (PAI) for defect passivation. We found that PAI can result in higher-efficiency cells by reducing the defects and suppressing non-radiative recombination. Consequently, n-i-p perovskite solar cells with a certificated efficiency of 21% were obtained. In addition, PAI exhibited excellent performance in p-i-n devices by serving as a buried interface layer, leading to an improved efficiency of 23%. [ABSTRACT FROM AUTHOR]

Halide perovskites demonstrate excellent optoelectronic characteristics such as large light absorption coefficients, long charge carrier diffusion lengths, and high charge carrier mobility. With these benefits, halide perovskites have been considered as a next-generation photoactive materials and introduced to diverse optoelectronic devices. Among them, perovskite solar cells (PSCs) and photodetectors (PPDs) have been paid attention, which have in common that they transform the light signals into photocurrent. In particular, great innovations have been achieved in improving the performance of PSCs and PPDs. With this regard, in this perspective, we have explained the development and recent progress in PSCs and PPDs. In addition, future research directions have also been outlined. This perspective summarizes the recent advances in halide perovskites for optoelectronic devices including solar cells and photodetectors and provides the guideline for further research direction in the field. [ABSTRACT FROM AUTHOR]

Halide perovskites with naturally coupled electron‐ion dynamics hold great potential for nonvolatile memory applications. Self‐rectifying memristors are promising as they can avoid sneak currents and simplify device configuration. Here we report a self‐rectifying memristor firstly achieved in a single perovskite (NHCINH3)3PbI5 (abbreviated as (IFA)3PbI5), which is sandwiched by Ag and ITO electrodes as the simplest cell in a crossbar array device configuration. The iodide ions of (IFA)3PbI5 can be easily activated, of which the migration in the bulk contributes to the resistance hysteresis and the reaction with Ag at the interface contributes to the spontaneous formation of AgI. The perfect combination of n‐type AgI and p‐type (IFA)3PbI5 gives rise to the rectification function like a p–n diode. Such a self‐rectifying memristor exhibits the record‐low set power consumption and voltage. This work emphasizes that the multifunction of ions in perovskites can simplify the fabrication procedure, decrease the programming power, and increase the integration density of future memory devices. [ABSTRACT FROM AUTHOR]

Quantum wells and superlattices are key building blocks in the semiconductor industry, normally fabricated using epitaxial growth techniques, such as vapor phase epitaxy, metalorganic chemical vapor deposition and molecular beam epitaxy. However, these complicated preparation processes, as well as their high cost, limit their extensive applications. It is essential to develop a simple solution process for building superstructures. Here, we demonstrate an ion exchange strategy for synthesizing an all-inorganic superlattice cesium lead bromide/layered double hydroxides (CsPbBr3/LDH) in solution. At room temperature, the perovskite ions diffuse into the interlayer of LDH and assemble into layered perovskite with various thicknesses. Compared with traditional organic-inorganic hybrid perovskite superlattice, the all-inorganic perovskite superlattice CsPbBr3/LDH has weak quantum confinement, which exhibits narrow emission line-widths of 20 nm, high quantum yields of 55%, and radiative lifetimes of several ns. Our findings offer a new route to synthesize novel perovskite superlattices and enrich the perovskite supercrystal platform for electronics, photonics and optoelectronics devices. [ABSTRACT FROM AUTHOR]

Abstract Lithium metal solid‐state battery is the first choice of batteries for electromobiles and consumer electronic products because of the specific capacity of 3860 mAh g−1 and high electrochemical potential (−3.04 V) of Li metal. Flexible polymer solid electrolytes have become the optimal solution to produce high energy density lithium batteries with arbitrary size and shape. In this work, we introduce a halide perovskite, CsSnI3, into the polyethylene oxide/lithium bis‐(trifluoromethanesuphone)imide (PEO–LiTFSI) polymer matrix. The CsSnI3 could form a LixSn alloy with Li, leading to homogenization of the electric field and Li+‐flux at the interface, Sn atom also bonds with the TFSI− anion to provide more dissociated Li+. Besides that, the I atom could interact with Li to form an electronic insulation with a strong blocking effect on electron tunneling. As a proof of concept, the synergy mechanism of the PEO–LiTFSI–CsSnI3 electrolyte improves the stable cycle life of the symmetric battery to more than 500 h, and the Li+ conductivity raised to 6.1 × 10−4 S cm−1 at 60°C. The application of the “zwitter ions analog” halide perovskite in PEO–LiTFSI provides a new choice among various methods to improve the electrochemical performance of polymer solid‐state batteries.

There exist some perovskites materials with no photoluminescence (PL), which will greatly limit the practical applications in photodetection, display and lighting. Here, we achieve an exotic pressure-induced emission (PIE) at a mild pressure of 0.8 GPa from initially non-emissive 2D all-inorganic perovskite Cs3Sb2Br9 quantum dots, when the sample was subjected to external pressure. With the increase of pressure, the PL intensity gradually increases and the emission color transforms from red to green. Combined with subsequent experiments and computations, thus PIE behavior and piezochromism result from the SbBr6 octahedral distortion, accompanied by a structural phase transition from trigonal to monoclinic under pressure. Our work provides a robust strategy to boost the emission efficiency and to construct multi-functional PIE materials with piezochromism in environmentally friendly perovskites, thus facilitating the diverse applications in futural practices.

Realizing narrow‐band green phosphors with high efficiency and thermal stability remains an enormous challenge for light‐emitting diodes (LEDs) backlighting in the pursuit of wide‐gamut display. Inspired by excellent and characteristic green sharp line emission of rare‐earth ion Tb3+, the rare‐earth‐based halide double perovskite Cs2NaTbCl6 phosphor with line‐shape emission (FWHM: ≈7 nm) at 547 nm is developed. The introduction of sensitizers Ce3+ or Sb3+ enhanced the quantum yield of Cs2NaTbCl6 to 76% or 90% from 52% due to the strong absorption of sensitizer and efficient energy transfer from sensitizers to Tb3+. The phosphors with or without sensitizer express better thermal stability than traditional perovskite, which originated from the phonon assistance, low thermal ionization probability, stronger localization of 4f electrons through the spectrum, and first‐principles calculation. The warm white LED fabricated using the present green emitting phosphor exhibits low color temperature of 3081 K and ≈100% of the NTSC gamut, which indicates that the Ce3+ or Sb3+ sensitized Cs2NaTbCl6 phosphors possess great application potential in WLED illumination and display fields. [ABSTRACT FROM AUTHOR]

Halide perovskites emerge as promising candidates for thermoelectrics due to their ultralow thermal conductivity. The conventional theory based on the phonon gas model, which treats thermal transport as particle‐like behavior, shows limitations to describe the unusual thermal transport property in some halide perovskites with strong anharmonicity. Here, the significance of phonon coherence effect on thermal transport of bismuth‐halide perovskite Cs3Bi2Br9 is reported by inelastic neutron scattering and simulations including density functional theory and machine‐learning potential based molecular dynamics. This study shows that the restrictive low‐energy acoustic phonons lead to the limited particle‐like thermal conductivity, which seriously underestimates the lattice thermal conductivity of Cs3Bi2Br9. The significant contribution of wave‐like optical phonon modes, driven by the coherence effect, accounts for an additional ≈50% wave‐like thermal conductivity. Besides, the experimental weak temperature dependence of thermal conductivity along z direction (κ ≈T−0.35) is well reproduced by calculation (κ ≈T−0.37) when including phonon coherence. This work highlights the critical role of phonon coherence in Cs3Bi2Br9 and enhances understanding on the unusual thermal transport properties in halide perovskites and other related materials with strong anharmonicity. [ABSTRACT FROM AUTHOR]

Dion–Jacobson‐type 2D halide perovskites (DJPs) present an ideal alternative to their 3D counterparts due to their superior stability and exceptional optoelectronic properties. Despite the numerous DJPs proposed in recent years, the impact of different spacer cations on DJPs remains unclear. This understanding is crucial for researchers to select suitable materials and is an urgent requirement for the development of higher‐performance DJPs‐based devices. In this study, the influence of the chain‐like spacer cations with varying branch chains and chain lengths is thoroughly examined using both theoretical and experimental methods. The findings reveal that spacer cations with high polarity components along the main chain direction enhance the stability and photoelectric properties of DJPs. Additionally, it is found that the chain length of the spacer cation plays a critical role. Chain lengths that are too long or too short can detrimentally affect the photoelectric performance and stability of DJPs. These insights will guide researchers in selecting suitable spacer cations and in innovating new types of DJPs. [ABSTRACT FROM AUTHOR]

The In‐based double perovskite halides have been widely studied for promising optical‐electric applications. The halide hexagonal perovskite Cs2LiInCl6 was isolated using solid‐state reactions and investigated using X‐ray diffraction and solid‐state NMR spectra. The material adopts a 12‐layered hexagonal structure (12R) consisting of layered cationic orders driven by the cationic charge difference and has Li+ cations in the terminal site and In3+ in the central site of face‐shared octahedron trimers. Such a cationic ordering pattern is stabilized by electrostatic repulsions between the next‐nearest neighboring cations in the trimers. The LiCl6 octahedron displays large distortion and is confirmed by 7Li SS NMR in the Cs2LiInCl6. The Cs2LiInCl6 material has a direct bandgap of ~4.98 eV. The Cs2LiInCl6: Mn2+ displays redshift luminescence (centered at ~610–622 nm) from the substituted Mn2+ emission in octahedron with larger PLQY (17.8 %–48 %) compared with that of Cs2NaInCl6: Mn2+. The Mn‐doped materials show luminescent concentration quenching and thermal quenching. The composition Cs2Li0.99In0.99Mn0.02Cl6 exhibits the highest PL intensity, a maximum PLQY of 48 %, and high luminescent retention rate of ~86 % below 400 K and is suitable for application for pc‐LED. These findings contribute to our understanding of the chloride perovskites and hold potential for widespread optical applications. [ABSTRACT FROM AUTHOR]

As a new type of semiconductor material, halide perovskite materials has the advantages of low cost and excellent photoelectric conversion performance. Various photoelectric devices based on the halide perovskite materials have begun to be gradually applied. Polycrystalline thin films are still the main research direction, however, they have the disadvantages of disordered morphology and many impurities. In contrast, single crystals have the characteristics of no grain boundaries and low defects. Therefore, the research based on large-size single crystals gained widely concerned. In this paper, a set of internal and external reverse temperature control cycle filtration growth devices was designed. The CH3NH3PbBr3 single crystal with a diameter of more than 60 mm was prepared by the combination of inverse temperature crystallization and seed crystal. The phase, microstructure, and optical and electrical properties of the crystal samples were studied. The crystal belongs to the cubic system with space group of Pm3m. The ultraviolet-visible absorption spectrum shows that the absorption cut-off edge is about 576 nm and the fluorescence emission spectrum peak is 552 nm. The rocking curve shows that the half width at maximum of the crystal (100) plane is 91. 42". The wafer after cutting and polishing is sensitive to photo response, and the on-off ratio is 2. 4 x 104. [ABSTRACT FROM AUTHOR]

The thermal transport and thermoelectric properties of CsCdX3 (X = Cl, Br) were investigated using first-principles calculations and machine learning interatomic potentials. The lattice thermal conductivity was obtained including the effect of temperature on the phonon dispersion spectrum and the contribution of the diffuson-like phonons, based on the self-consistent phonon (SCP) and two-channel phonon transport theories. We found that diffuson-like phonons contribute significantly to the lattice thermal transport. The ultralow lattice thermal conductivities of CsCdCl3 and CsCdBr3 at 300 K are 0.95 W/mK and 0.57 W/mK, respectively. The large Seebeck coefficient of CsCdCl3 and CsCdBr3 is about 800 μV/K and 700 μV/K at 900 K, due to the multi-valley energy band structure. The calculated maximum ZT of p-type CsCdBr3 is 1.16 at 900 K, larger than most of the reported halide perovskite materials. We suggest that CsCdBr3 is a promising candidate for thermoelectric halide perovskite materials. [ABSTRACT FROM AUTHOR]

A CsPbBr3@Ag-C3N4 ternary heterojunction photocatalyst with g-C3N4 as ballistic electron transport "tunnel" is designed and synthesized. The photogenerated electrons of CsPbBr3 dots can be efficiently transferred to Ag nanoparticles via g-C3N4 sheets, resulting in efficient CO2 reduction. The structured design of catalyst provides a novel insight for the development of perovskite-based photocatalysts. [Display omitted] • CsPbBr 3 @Ag-C 3 N 4 ternary heterojunction photocatalyst is designed and synthesized. • The photogenerated electrons of CsPbBr 3 QDs can be efficiently transferred to Ag nanoparticles via g-C 3 N 4 as the electron transport tunnel. • The CsPbBr 3 @Ag-C 3 N 4 ternary photocatalyst achieves a conversion rate of 19.49 μmol·g−1·h−1 with almost 100 % CO selectivity. • In situ DRIFT and DFT calculations reveal the photocatalytic mechanism for CO 2 reduction. Perovskite CsPbBr 3 quantum dot shows great potential in artificial photosynthesis, attributed to its outstanding optoelectronic properties. Nevertheless, its photocatalytic activity is hindered by insufficient catalytic active sites and severe charge recombination. In this work, a CsPbBr 3 @Ag-C 3 N 4 ternary heterojunction photocatalyst is designed and synthesized for high-efficiency CO 2 reduction. The CsPbBr 3 quantum dots and Ag nanoparticles are chemically anchored on the surface of g-C 3 N 4 sheets, forming an electron transfer tunnel from CsPbBr 3 quantum dots to Ag nanoparticles via g-C 3 N 4 sheets. The resulting CsPbBr 3 @Ag-C 3 N 4 ternary photocatalyst, with spatial separation of photogenerated carriers, achieves a remarkable conversion rate of 19.49 μmol·g−1·h−1 with almost 100 % CO selectivity, a 3.13-fold enhancement in photocatalytic activity as compared to CsPbBr 3 quantum dots. Density functional theory calculations reveal the rapid CO 2 adsorption/activation and the decreased free energy (0.66 eV) of *COOH formation at the interface of Ag nanoparticles and g-C 3 N 4 in contrast to the g-C 3 N 4 , leading to the excellent photocatalytic activity, while the thermodynamically favored CO desorption contributes to the high CO selectivity. This work presents an innovative strategy of constructing perovskite-based photocatalyst by modulating catalyst structure and offers profound insights for efficient CO 2 conversion. [ABSTRACT FROM AUTHOR]

Lithium metal solid‐state battery is the first choice of batteries for electromobiles and consumer electronic products because of the specific capacity of 3860 mAh g−1 and high electrochemical potential (−3.04 V) of Li metal. Flexible polymer solid electrolytes have become the optimal solution to produce high energy density lithium batteries with arbitrary size and shape. In this work, we introduce a halide perovskite, CsSnI3, into the polyethylene oxide/lithium bis‐(trifluoromethanesuphone)imide (PEO–LiTFSI) polymer matrix. The CsSnI3 could form a LixSn alloy with Li, leading to homogenization of the electric field and Li+‐flux at the interface, Sn atom also bonds with the TFSI− anion to provide more dissociated Li+. Besides that, the I atom could interact with Li to form an electronic insulation with a strong blocking effect on electron tunneling. As a proof of concept, the synergy mechanism of the PEO–LiTFSI–CsSnI3 electrolyte improves the stable cycle life of the symmetric battery to more than 500 h, and the Li+ conductivity raised to 6.1 × 10−4 S cm−1 at 60°C. The application of the "zwitter ions analog" halide perovskite in PEO–LiTFSI provides a new choice among various methods to improve the electrochemical performance of polymer solid‐state batteries. [ABSTRACT FROM AUTHOR]

There exist some perovskites materials with no photoluminescence (PL), which will greatly limit the practical applications in photodetection, display and lighting. Here, we achieve an exotic pressure-induced emission (PIE) at a mild pressure of 0.8 GPa from initially non-emissive 2D all-inorganic perovskite Cs3Sb2Br9 quantum dots, when the sample was subjected to external pressure. With the increase of pressure, the PL intensity gradually increases and the emission color transforms from red to green. Combined with subsequent experiments and computations, thus PIE behavior and piezochromism result from the SbBr6 octahedral distortion, accompanied by a structural phase transition from trigonal to monoclinic under pressure. Our work provides a robust strategy to boost the emission efficiency and to construct multi-functional PIE materials with piezochromism in environmentally friendly perovskites, thus facilitating the diverse applications in futural practices. [ABSTRACT FROM AUTHOR]

Ultrathin halide perovskites have drawn tremendous attention in nano‐/micro‐optoelectronic devices due to their fascinating performance and capability for chip integration. Unfortunately, it is highly challenging to obtain large‐scale and chronically stable ultrathin halide perovskites for practical application. Herein, the universal low‐temperature vapor‐phase synthesis of ultrathin perovskite family materials with thickness down to 2D level and lateral size up to 1.5 cm × 1.5 cm is reported by developing a self‐limiting chemical vapor deposition strategy. The perovskite products are found to exhibit superior stability over 180 days under an air environment. The resultant photodetectors demonstrate charming optoelectronic properties such as superior responsivity (3.7 × 103 A W−1), ultrafast response time (<10 µs), and outstanding low‐level light image sensing capability. This universal perovskite synthesis strategy offers great potential for practical applications of halide perovskites in future nano‐/micro‐optoelectronic devices. [ABSTRACT FROM AUTHOR]

Halide perovskite materials have broad prospects for applications in various fields such as solar cells, LED devices, photodetectors, fluorescence labeling, bioimaging, and photocatalysis due to their bandgap characteristics. This study compiled experimental data from the published literature and utilized the excellent predictive capabilities, low overfitting risk, and strong robustness of ensemble learning models to analyze the bandgaps of halide perovskite compounds. The results demonstrate the effectiveness of ensemble learning decision tree models, especially the gradient boosting decision tree model, with a root mean square error of 0.090 eV, a mean absolute error of 0.053 eV, and a determination coefficient of 93.11%. Research on data related to ratios calculated through element molar quantity normalization indicates significant influences of ions at the X and B positions on the bandgap. Additionally, doping with iodine atoms can effectively reduce the intrinsic bandgap, while hybridization of the s and p orbitals of tin atoms can also decrease the bandgap. The accuracy of the model is validated by predicting the bandgap of the photovoltaic material MASn1−xPbxI3. In conclusion, this study emphasizes the positive impact of machine learning on material development, especially in predicting the bandgaps of halide perovskite compounds, where ensemble learning methods demonstrate significant advantages. [ABSTRACT FROM AUTHOR]

Component doping is the fundamental topic for modulating the properties of semiconductor materials. The introduction of doping ions into lead halide perovskites (LHPs) can not only maintain the excellent photoelectric properties but also enhance the stability of LHPs in open air and thermal environments. However, due to the "self-purification" effect in crystallography, there is an inherent trend to pop doping ions out of LHPs lattice. In this work, it is confirmed that in Mn2+ doped LHPs nanocrystals (NCs) the discharge of Mn2+ will be accelerated at higher temperatures. It is also proved that even at room temperature, the dopants in LHPs NCs will also actively "migrate", resulting in declined optical performance. Therefore, for cation alloying/doping LHPs NCs, the migration of doping ions in the material should be considered in addition to the intrinsic halide migration characteristics. This work will provide a benign reference for application of doped LHPs NCs. [ABSTRACT FROM AUTHOR]

Abstract Halide perovskites with naturally coupled electron‐ion dynamics hold great potential for nonvolatile memory applications. Self‐rectifying memristors are promising as they can avoid sneak currents and simplify device configuration. Here we report a self‐rectifying memristor firstly achieved in a single perovskite (NHCINH3)3PbI5 (abbreviated as (IFA)3PbI5), which is sandwiched by Ag and ITO electrodes as the simplest cell in a crossbar array device configuration. The iodide ions of (IFA)3PbI5 can be easily activated, of which the migration in the bulk contributes to the resistance hysteresis and the reaction with Ag at the interface contributes to the spontaneous formation of AgI. The perfect combination of n‐type AgI and p‐type (IFA)3PbI5 gives rise to the rectification function like a p–n diode. Such a self‐rectifying memristor exhibits the record‐low set power consumption and voltage. This work emphasizes that the multifunction of ions in perovskites can simplify the fabrication procedure, decrease the programming power, and increase the integration density of future memory devices.

Halide perovskites belong to an important family of semiconducting materials with electronic properties that enable a myriad of applications, especially in photovoltaics and optoelectronics. Their optical properties, including photoluminescence quantum yield, are affected and notably enhanced at crystal imperfections where the symmetry is broken and the density of states increases. These lattice distortions can be introduced through structural phase transitions, allowing charge gradients to appear near the interfaces between phase structures. In this work, we demonstrate controlled multiphase structuring in a single perovskite crystal. The concept uses cesium lead bromine (CsPbBr3) placed on a thermoplasmonic TiN/Si metasurface and enables single-, double-, and triple-phase structures to form on demand above room temperature. This approach promises application horizons of dynamically controlled heterostructures with distinctive electronic and enhanced optical properties.

In backlighting systems for liquid crystal displays, conventional red, green, and blue (RGB) light sources that lack polarization properties can result in a significant optical loss of up to 50% when passing through a polarizer. To address this inefficiency and optimize energy utilization, this study presents a high-performance device designed for RGB polarized emissions. The device employs an array of semipolar blue µLEDs with inherent polarization capabilities, coupled with mechanically stretched films of green-emitting CsPbBr3 nanorods and red-emitting CsPbI3-Cs4PbI6 hybrid nanocrystals. The CsPbBr3 nanorods in the polymer film offer intrinsic polarization emission, while the aligned-wire structures formed by the stable CsPbI3-Cs4PbI6 hybrid nanocrystals contribute to substantial anisotropic emissions, due to their high dielectric constant. The resulting device achieved RGB polarization degrees of 0.26, 0.48, and 0.38, respectively, and exhibited a broad color gamut, reaching 137.2% of the NTSC standard and 102.5% of the Rec. 2020 standard. When compared to a device utilizing c-plane LEDs for excitation, the current approach increased the intensity of light transmitted through the polarizer by 73.6%. This novel fabrication approach for polarized devices containing RGB components holds considerable promise for advancing next-generation display technologies.

Zinc (Zn) has arisen as a significant suppressor of vacancy formation in halide perovskites, establishing its pivotal role in defect engineering for these materials. Herein, the Zn‐catalyzed vapor‐liquid‐solid (VLS) route is reported to render black‐phase CsPbI3 nanowires (NWs) operationally stable at room temperature. Based on first‐principle calculations, the doped Zn2+ can not only lead to the partial crystal lattice distortion but also reduce the formation energy (absolute value) from the black phase to the yellow phase, improving the stability of the desired black‐phase CsPbI3 NWs. A series of contrast tests further confirm the stabilization effect of the Zn‐doped strategy. Besides, the polarization‐sensitive characteristics of black‐phase CsPbI3 NWs are revealed. This work highlights the importance of phase stabilization engineering for CsPbI3 NWs and their potential applications in anisotropic optoelectronics. [ABSTRACT FROM AUTHOR]

The chiral organic–inorganic halide perovskites (OIHPs) are vital candidates for superior nonlinear optical (NLO) effects associated with circularly polarized (CP) light. NLO in chiral materials often couples with magnetic dipole (MD) transition, as well as the conventional electric dipole (ED) transition. However, the importance of MD transition in NLO process of chiral OIHPs has not yet been well recognized. Here, the circular polarized probe analysis of second harmonic generation circular dichroism (SHG‐CD) provides the direct evidence that the contribution of MD leads to a large anisotropic response to CP lights in chiral OIHPs, (R‐/S‐MBACl)2PbI4. The thin films exhibit great sensitivity to CP lights over a wide wavelength range, and the g‐value reaches up to 1.57 at the wavelength where the contribution of MD is maximized. Furthermore, it is also effective as CP light generator, outputting CP‐SHG with maximum g‐factor of 1.76 upon the stimulation of linearly polarized light. This study deepens the understanding of relation between chirality and magneto‐optical effect, and such an efficient discrimination and generation of CP light signal is highly applicable for chirality‐based sensor and optical communication devices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Halide perovskite phosphor with high quantum efficiency. • Machine learning model for material design. • Enhancing self-trapped exciton emission by tuning ion radius. • White light LED with commercial potential. The outstanding emission of halide perovskites make them ideal candidates for white emission light-emitting diodes (LEDs) for lighting applications. However, many perovskites contain toxic or scarce elements and have unsatisfactory stability. Here, we report a target-driven approach, based on active learning (AL) techniques, to discover halide perovskites suitable for commercial LED applications. Based on the similarity between halide and oxide perovskites, a model trained on an oxide perovskite dataset plus six AL-selected halide perovskites exhibited excellent performance for photoluminescence quantum yield (PLQY) predictions of oxide and halide perovskites. The model proposed a strong relationship between ionic radii and PLQY, postulated to be due to the self-trap excitons derived from the Jahn-Teller deformation. A novel halide perovskite phosphor, Cs 4 Zn(Bi 0.85 Sb 0.15) 2 Cl 12 :0.01Mn, was designed and synthesized with the aid of the model. It exhibited an 88 % PLQY and outstanding thermal and luminescent stability. A simple white LED was fabricated from this material, exemplifying its commercial potential. This study demonstrates how machine learning techniques can accelerate discovery of next-generation phosphors for high performance single emitter-based white-light emitting devices. [ABSTRACT FROM AUTHOR]

Halide perovskite Cs3Bi2Br9 (CBB) has excellent potential in photocatalysis due to its promising light-harvesting properties. However, its photocatalytic performance might be limited due to the unfavorable charge carrier migration and water-induced properties, which limit the stability and photocatalytic performance. Therefore, we address this constraint in this work by synthesizing a stable halide perovskite heterojunction by introducing hydrogen titanate nanosheets (H2Ti3O7-NS, HTiO-NS). Optimizing the weight % (wt%) of CBB enables synthesizing the optimal CBB/HTiO-NS, CBHTNS heterostructure. The detailed morphology and structure characterization proved that the cubic shape of CBB is anchored on the HTiO-NS surface. The 30 wt% CBB/HTiO-NS-30 (CBHTNS-30) heterojunction showed the highest BnOH photooxidation performance with 98% conversion and 75% benzoic acid (BzA) selectivity at 2 h under blue light irradiation. Detailed optical and photoelectrochemical characterization showed that the incorporating CBB and HTiO-NS widened the range of the visible-light response and improved the ability to separate the photo-induced charge carriers. The presence of HTiO-NS has increased the oxidative properties, possibly by charge separation in the heterojunction, which facilitated the generation of superoxide and hydroxyl radicals. A possible reaction pathway for the photocatalytic oxidation of BnOH to BzH and BzA was also suggested. Furthermore, through scavenger experiments, we found that the photogenerated h+, e− and •O2− play an essential role in the BnOH photooxidation, while the •OH have a minor effect on the reaction. This work may provide a strategy for using HTiO-NS-based photocatalyst to enhance the charge carrier migration and photocatalytic performance of CBB. [ABSTRACT FROM AUTHOR]

Heterojunction semiconductors have been extensively applied in various optoelectronic devices due to their unique carrier transport characteristics. However, it is still a challenge to construct heterojunctions based on colloidal quantum dots (CQDs) due to stress and lattice mismatch. Herein, HgSe/CsPbBrxI3−x heterojunctions with type I band alignment are acquired that are derived from minor lattice mismatch (~1.5%) via tuning the ratio of Br and I in halide perovskite. Meanwhile, HgSe CQDs with oleylamine ligands can been exchanged with a halide perovskite precursor, acquiring a smooth and compact quantum dot film. The photoconductive detector based on HgSe/CsPbBrxI3−x heterojunction presents a distinct photoelectric response under an incident light of 630 nm. The work provides a promising strategy to construct CQD-based heterojunctions, simultaneously achieving inorganic ligand exchange, which paves the way to obtain high-performance photodetectors based on CQD heterojunction films. [ABSTRACT FROM AUTHOR]

Low‐dimensional hybrid bismuth halide perovskites have recently emerged as a class of non‐toxic alternative to lead perovskites with promising optoelectronic properties. Here, we report three hybrid bismuth(III)‐iodides: 0‐D (H2DAC)2Bi2I10 ⋅ 6H2O (H2DAC_Bi_I), 0‐D (H2DAF)4Bi2I10 ⋅ 2I3 ⋅ 2I ⋅ 6H2O (H2DAF_Bi_I), and 1‐D (H2DAP)BiI5 (H2DAP_Bi_I) (where H2DAC=trans‐1,4‐diammoniumcyclohexane; H2DAF=2,7‐diammoniumfluorene and H2DAP=1,5‐diammoniumpentane). Their synthesis, single‐crystal X‐ray structures, and photophysical properties are reported. The first two compounds comprise edge‐sharing [Bi2I10]4− dimers, while the last compound has cis‐corner‐sharing 1‐D chains of [BiI6]3− octahedra. Intercalation of triiodide (I3−) and iodide (I−) ions enhance electronic coupling between the [Bi2I10]4− of H2DAF_Bi_I, leading to enhanced optical absorption, compared to H2DAC_Bi_I which lacks such intercalants. Furthermore, calorimetric and variable temperature X‐ray diffraction measurements suggest a centrosymmetric to non‐centrosymmetric phase transition (monoclinic P212121↔orthorhombic Pnma) of H2DAP_Bi_I at 448 K (in heating step) and at 443 K (in cooling step). [ABSTRACT FROM AUTHOR]

In this work, an n-i-p perovskite solar cell structure comprising a lead-free methyl ammonium iodide (CH3NH3SnI3) as an absorber layer and Cuprous Tricynate (CuSCN) as a hole transport material is numerically modeled and simulated using SCAPS-1D software. Influence of various material parameters such as doping concentration of the absorber layer, thickness of the different layers, effect of different back contacts, defects in the absorber layer etc., is studied as a function of cell parameters, i.e., fill factor (FF), the open circuit voltage (Voc), the short circuit current density (Jsc), and the power conversion efficiency (PCE) to explore the photovoltaic performance of the designed solar cell structure. Upon optimization of the different material parameters, the modelled solar cell has resulted in enhanced photovoltaic performance with Voc ~ 1.08 V, Jsc = 33.78 mA/cm2, FF = 87.42% and PCE = 32.00%. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have garnered remarkable attention for their efficiency and tunable optoelectronic properties. However, their instability to moisture and heat poses challenges. Traditional trial‐and‐error approaches for finding stable halide perovskites are inefficient due to the vast compositional possibilities within ABX3 perovskite structure. This study uses machine learning (ML) to predict bandgaps and photovoltaic parameters of PSCs, using a dataset of 447 data points containing chemical composition, bandgaps, and photovoltaic parameters. Various ML models including support vector regressor, random forest, gradient boost regressor, XGBoost, extratree Regressor, and AdaBoost Regressor have been used herein. Positional average elemental property (PAEP) approach is introduced to featurize the data. As ABX3 perovskite involves distinct A, B, and X sites, the proposed PAEP model captures site‐specific effects, enhancing model accuracy. The best model exhibits impressive r‐values of 0.98 for bandgap prediction and 0.86 for power conversion efficiency of PSCs. Elemental properties of B and X sites, such as ionization energy, electron affinity, and electronegativity, are found to be crucial features in the analysis by Shapley additive explanation. This study underscores the potential of ML in designing novel, stable, and efficient PSCs, offering a more efficient alternative to conventional trial‐and‐error methods. [ABSTRACT FROM AUTHOR]

With the emergence of the Internet of Things (IoT) and the rapid growth of big data generated by edge devices, there has been a growing need for electronic devices that are capable of processing and transmitting data at low power and high speeds. Traditional Complementary Metal-Oxide-Semiconductor (CMOS) devices are nonvolatile and often limited by their ability for certain IoT applications due to their unnecessary power consumption for data movement in von Neuman architecture-based systems. This has led to a surge in research and development efforts aimed at creating innovative electronic components and systems that can overcome these shortcomings and meet the evolving needs of the information era, which share features such as improved energy efficiency, higher processing speeds, and increased functionality. Memristors are a novel type of electronic device that has the potential to break down the barrier between storage and computing. By storing data and processing information within the same device, memristors can minimize the need for data movement, which allows for faster processing speeds and reduced energy consumption. To further improve the energy efficiency and reliability of memristors, there has been a growing trend toward diversifying the selection of dielectric materials used in memristors. Halide perovskites (HPs) have unique electrical and optical properties, including ion migration, charge trapping effect caused by intrinsic defects, excellent optical absorption efficiency, and high charge mobility, which makes them highly promising in applications of memristors. In this paper, we provide a comprehensive overview of the recent development in resistive switching behaviors of HPs and the underlying mechanisms. Furthermore, we summarize the diverse range of HPs, their respective performance metrics, as well as their applications in various fields. Finally, we critically evaluate the current bottlenecks and possible opportunities in the future research of HP memristors. [ABSTRACT FROM AUTHOR]

Metal halide perovskites are widely used in the preparation of photodetectors (PDs) due to their excellent photoelectric properties, tunable band gap, low cost, and rapid processing in solutions. Although 3D perovskite PDs exhibit exceptional performance, their practical applications are limited due to instability issues. Conversely, 2D perovskite PDs are gaining popularity due to their superior environmental stability. To produce efficient and stable perovskite‐based PDs, it is crucial to control the film formation process to achieve high‐quality perovskite films. This paper examines the impacts of perovskite film preparation process and crystallinity on the photoelectric properties of PDs and presents important observations regarding the crystallization and phase dynamics that occur during perovskite film formation. These insights have practical implications on the design and preparation of high‐performance and stable metal halide perovskite photodetectors, particularly in the domains of optical communications and imaging. They offer valuable guidance for next researchers and developers seeking to improve the functionality and marketability of photodetectors using perovskite films. [ABSTRACT FROM AUTHOR]

Halide perovskite materials have attracted worldwide attention in the photovoltaic area due to the rapid improvement in efficiency, from less than 4% in 2009 to 26.1% in 2023 with only a nanometer lever photo-active layer. Meanwhile, this nova star found applications in many other areas, such as light emitting, sensor, etc. This review started with the fundamentals of physics and chemistry behind the excellent performance of halide perovskite materials for photovoltaic/light emitting and the methods for preparing them. Then, it described the basic principles for solar cells and light emitting devices. It summarized the strategies including nanotechnology to improve the performance and the application of halide perovskite materials in these two areas: from structure–property relation to how each component in the devices affects the overall performance. Moreover, this review listed the challenges for the future applications of halide perovskite materials. [ABSTRACT FROM AUTHOR]

The halide perovskite TiF3, renowned for its intricate interplay between structure, electronic correlations, magnetism, and thermal expansion, is investigated. Despite its simple structure, understanding its low‐temperature magnetic behavior has been a challenge. Previous theories propose antiferromagnetic ordering. In contrast, experimental signatures for an ordered magnetic state are absent down to 10 K. The current study has successfully reevaluated the theoretical modeling of TiF3, unveiling the significance of strong electronic correlations as the key driver for its insulating behavior and magnetic frustration. In addition, frequency‐dependent optical reflectivity measurements exhibit clear signs of an insulating state. The analysis of the calculated magnetic data gives an antiferromagnetic exchange coupling with a net Weiss temperature of order 25 K as well as a magnetic response consistent with a S = 1/2 local moment per Ti3+. Yet, the system shows no susceptibility peak at this temperature scale and appears free of long‐range antiferromagnetic order down to 1 K. Extending ab initio modeling of the material to larger unit cells shows a tendency for relaxing into a noncollinear magnetic ordering, with a shallow energy landscape between several magnetic ground states, promoting the status of this simple, nearly cubic perovskite structured material as a candidate spin liquid. [ABSTRACT FROM AUTHOR]

The A4BX6 molecular halide perovskites have received attention owing to their interesting optoelectronic properties at the molecular scale; however, a comprehensive dataset of their atomic structures and electronic properties and associated data-driven investigation are still unavailable now, which makes it difficult for inverse materials design for semiconductor applications (e.g. wide band gap semiconductor). In this manuscript, we employ data-driven methods to predict band gaps of A4BX6 molecular halide perovskites via machine learning. A large virtual design database including 246 904 A4BX6 perovskite samples is predicted via machine learning, based on the model trained using 2740 first-principles results of A4BX6 molecular halide perovskites. In addition, symbolic regression-based machine learning is employed to identify more physically intuitive descriptors based on the starting first-principles dataset of A4BX6 molecular halide perovskites. In addition, different ranking methods are employed to offer a comprehensive feature importance analysis for the halide perovskite materials. This study highlights the efficacy of machine learning-assisted compositional design of A4BX6 perovskites, and the multi-dimensional database established here is valuable for future experimental validation toward perovskite-based wide band gap semiconductor materials. [ABSTRACT FROM AUTHOR]

A reasonable and general method was designed and constructed composites Al-BDC(–NH 2) and Cs 3 Bi 2 Br 9 as bifunctional electrocatalysts for electrochemical overall water splitting. The obtained Al-BDC(–NH 2)@CBB catalysts can stabilize for at least 10 h under all pH conditions (acidic, neutral, and alkaline solutions) for electrochemical properties (e.g., HER, OER, and OWS), realizing a dual-function electrocatalyst design strategy. [Display omitted] Electrochemical water splitting is one of the most active areas of energy research, yet the benchmark electrocatalysts used for this area are based on expensive noble metals and transition metals, thus mainly reactions in alkaline solution. MOFs and halide perovskite are novel electrochemical catalysts but unstable in water basically. Here we report a study on composites of (NH 2)-MIL-53(Al) MOFs and CBB halide perovskite (Cs 3 Bi 2 Br 9), which exhibit obvious activity for overall electrochemical water splitting for long-term stability with little deactivation after 10 h in all pH solutions. [ABSTRACT FROM AUTHOR]

The halide perovskite TiF3, renowned for its intricate interplay between structure, electronic correlations, magnetism, and thermal expansion, is investigated. Despite its simple structure, understanding its low‐temperature magnetic behavior has been a challenge. Previous theories propose antiferromagnetic ordering. In contrast, experimental signatures for an ordered magnetic state are absent down to 10 K. The current study has successfully reevaluated the theoretical modeling of TiF3, unveiling the significance of strong electronic correlations as the key driver for its insulating behavior and magnetic frustration. In addition, frequency‐dependent optical reflectivity measurements exhibit clear signs of an insulating state. The analysis of the calculated magnetic data gives an antiferromagnetic exchange coupling with a net Weiss temperature of order 25 K as well as a magnetic response consistent with a S = 1/2 local moment per Ti3+. Yet, the system shows no susceptibility peak at this temperature scale and appears free of long‐range antiferromagnetic order down to 1 K. Extending ab initio modeling of the material to larger unit cells shows a tendency for relaxing into a noncollinear magnetic ordering, with a shallow energy landscape between several magnetic ground states, promoting the status of this simple, nearly cubic perovskite structured material as a candidate spin liquid. [ABSTRACT FROM AUTHOR]