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Lead halide perovskites have been explored ardently in the past decade owing to their excellent photophysical properties. High‐temperature cation exchange reactions have been employed to improve the stability and performance in perovskite lattice, but lacks control over size, shape, and stoichiometry. Herein, the solution phase interaction of cesium lead bromide (CsPbBr3) nanocrystals with monovalent and bivalent copper ions, under ambient conditions is systematically investigated. The introduction of Cu1+ explicitly initiates a one‐dimensional growth with a distinct phase transition, that is from cubic to orthorhombic, while Cu2+ induces a partial exchange with Pb2+ with no phase change. DFT calculations suggest that Cu1+ induces structural distortion via Cs1+ substitution, altering the Goldschmidt tolerance factor and perovskite octahedral tilting, leading to the phase transition. Additionally, the oleic acid/amine ligands used to stabilize the nanocrystals, are preferentially etched away to form complexes with Cu1+, initializing an oriented growth of the nanocubes to nanorods. A mechanistic investigation of the evolution of the nanorods gave insights on tuning the tolerance factor via room temperature modifications and cation exchanges in perovskites for anisotropy and morphology tuning. This effortlessly obtained perovskite nanorods with Cu1+ could find effective applications in optoelectronics, and as novel photocatalysts. [ABSTRACT FROM AUTHOR]

Copyright of Micronanoelectronic Technology is the property of Micronanoelectronic Technology 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.)

Morphology plays a crucial role in defining the optical, electronic, and mechanical properties of halide perovskite microcrystals. Therefore, developing strategies that offer precise control over crystal morphology during the growth process is highly desirable. This work presents a simple scheme to simultaneously grow distinct geometries of cesium lead bromide (CsPbBr3) microcrystals, including microrods (MR), microplates (MP), and microspheres (MS), in a single chemical vapor deposition (CVD) experiment. By strategically adjusting precursor evaporation temperatures, flux density, and the substrate temperature, we surpass previous techniques by achieving simultaneous yet selective growth of multiple CsPbBr3 geometries at distinct positions on the same substrate. This fine growth control is attributed to the synergistic variation in fluid flow dynamics, precursor substrate distance, and temperature across the substrate, offering regions suitable for the growth of different morphologies. Pertinently, perovskite MR are grown at the top, while MP and MS are observed at the center and bottom regions of the substrate, respectively. Structural analysis reveals high crystallinity and an orthorhombic phase of the as-grown perovskite microcrystals, while persistent photonic lasing manifests their nonlinear optical characteristics, underpinning their potential application for next-generation photonic and optoelectronic devices. [ABSTRACT FROM AUTHOR]

In recent years, the development of new efficient, fast, and intuitive materials and methods for photoluminescence (PL) sensing has become a research hotspot in analytical chemistry. Lead halide perovskite (LHP) materials have the characteristics of adjustable PL properties, high PL efficiency, and a variety of synthesis methods. Their PL is also sensitive to the change in specific factors in the environment. Based on these characteristics, LHP has shown good application prospects in the field of optical sensing. The study of the structural dimension, organic composition, or doped ions of LHP is helpful in exploring its sensing potential and proposing new sensing mechanisms, which have important research significance to promote sensing applications. In this review, the PL characteristics and sensing mechanisms, as well as their sensing applications of two- and three dimensional LHP, are discussed and summarized. [ABSTRACT FROM AUTHOR]

Perovskite quantum dots (PeQDs) are promising nanoscale emitters in a generation of high-performance, large-area, and low-cost light-emitting diodes (LEDs) due to their superior emissive properties and excellent solution processability. Despite the tremendous advancement in luminescence efficiency in PeQDs, the design principle of the hole-transporting layer for PeQDs-based LEDs is still limited. Here, we investigate the discrepancy in electroluminescence properties of PeQDs-based LEDs with two widely used hole-transporting layers, namely, poly-[bis-(4-phenyl)-(2,4,6-trimethylphenyl)-amine] (PTAA) and poly-(9,9-dioctylfluorene-co-N-(4-(3-methylpropyl)) diphenylamine) (TFB). The results show that the TFB-based PeQD-LEDs exhibit much inferior performance than the PTAA-based device (7% vs 18% for external quantum efficiency) although the PeQDs show better optical properties when depositing on TFB hole-transporting layers. Theoretical calculation and comprehensive spectroscopic analysis indicate a weaker interaction between PeQDs and TFB polymers, which is attributed to the larger steric hindrance of TFB than that of PTAA. As a result, electrical characterizations identify a poor hole injection efficiency from the TFB to the PeQDs emissive layer when compared with the PTAA hole-transporting layers, thus leading to poor device performance. This work reveals the interaction between the hole-transporting layer and PeQDs on the performance of electroluminescence beyond the energy level and mobility of hole-transporting materials, which promotes an understanding of the hole injection mechanism in PeQDs-based LEDs. [ABSTRACT FROM AUTHOR]

X-ray and γ-ray detection have been extensively studied and applied in medical imaging, security inspection, homeland security, non-destructive testing and other various fields. Perovskite materials have become excellent candidates for radiation detector devices due to their high radiation absorption coefficient, high carrier mobility-lifetime product and defect tolerance. The solution method offers significant advantages in the preparation of perovskite materials. It is a cost-effective approach that can be carried out at low temperatures or under ambient conditions. Additionally, it is also easier to implement for industrial production. This method plays a crucial role in optimizing the material system and achieving the preparation of high quality and large area crystal materials in the future. This paper analyzes the effects of crystal growth and material composition on radiation detection performance, focusing on the solution preparation of perovskite materials. The study aims to improve radiation detection performance by optimizing crystal growth quality and device structure design. Additionally, it also summarises the challenges faced by perovskite materials in the field of radiation detection and suggests future research directions. The results of this study are expected to serve as a reference for the industrialization of perovskite materials in the field of radiation detection. [ABSTRACT FROM AUTHOR]

The vapor–solid reaction technique holds potential for producing large‐scale organic–inorganic perovskite films, using a two‐step deposition process. The sucess of perovskite formation heavily relies on the crystallization of lead iodide (PbI2) precursor films. However, the high crystallinity of PbI2 can hinder organic vapors' diffusion and negatively affecting the solar cells by increasing charge recombination and accelerating degradation. To address this, pyridinium trifluoromethanesulfonate (PTFS) is introduced into the PbI2 precursor solution to control the nucleation and growth of PbI2 films. PTFS has been found to effectively suppresses PbI2 crystallization and enhance the integration of formamidinium ion (FA+) through hydrogen bonding, facilitating the full transformation of PbI2 into perovskite. It also minimizes defect formation by interacting with uncoordinated Pb2+ and FA+ ions. These modifications have significantly enhanced power conversion efficiency (PCE), reaching up to 21.19%, and the devices have maintained 93% of their initial performance after 1580 h of exposure to air. [ABSTRACT FROM AUTHOR]

Lead halide perovskites have emerged as the next‐generation materials for self‐powered photodetectors enabling operation without an external power source. In this study, a planar‐type photodetector based on metal‐doped p‐type MAPbBr3/n‐type MAPbBr3 single crystal showing excellent self‐powered photodetection properties is presented. The p‐n junction on the MAPbBr3 single crystal is formed by controlled epitaxial growth of Ag+‐doped MAPbBr3 SC (p‐type) on the facet of Sb3+‐doped MAPbBr3 SC (n‐type). The as‐integrated p‐n junction device with asymmetric electrodes shows a typical photovoltaic behavior with a high open circuit voltage of 0.95 V and great sensitivity to 530 nm illumination at zero bias with a responsivity of up to 0.41 A W−1 and a specific detectivity of 6.39 × 1011 Jones, which are among the highest values reported for MAPbBr3 single crystal‐based self‐powered photodetectors. In addition, the rise time and fall time of this device are as fast as 14 and 10 ms, respectively. These results pave the way for the fabrication of self‐powered perovskite‐based p‐n junction photodiode, which may find potential application in advanced photodiode and future optoelectronic devices. [ABSTRACT FROM AUTHOR]

Lead halide perovskite nanocrystals (NCs) with narrow, bright emission in the visible range are promising candidates for light‐emitting applications. Near‐unity quantum yields have been realized for green and red‐emitting perovskites, but efficient, stable blue‐emitting perovskite materials are scarce. Current methods to synthesize quantum‐confined CsPbBr3 NCs with blue emission are limited to specific wavelength ranges and still suffer from inhomogeneously broadened emission profiles. Herein, anisotropic blue‐green emitting CsPbBr3 NCs are synthesized in ambient atmosphere using a spontaneous crystallization method. Optical spectroscopy reveals a gradual, asymptotic photoluminescence (PL) redshift of pristine colloidal NCs after synthesis. During this process, the emission quality improves notably as the PL spectra become narrower and more symmetric, accompanied by a PL intensity increase. Electron microscopy indicates that the gradual redshift stems from an isotropic growth of the CsPbBr3 NCs in at least two dimensions, likely due to residual precursor ions in the dispersion. Most importantly, the growth process can be halted at any point by injecting an enhancement solution containing PbBr2 and organic capping ligands. Thus, excellent control over NC size is achieved, allowing for nanometer‐precise tunability of the respective emission wavelength in the range between 475 and 500 nm, enhancing the functionality of these already impressive NCs. [ABSTRACT FROM AUTHOR]

We examine halide anion-exchange reactions on CsPbX3 nanorods (NRs), and we identify reaction conditions that provide complete anion exchange while retaining both the highly quantum-confined 1-D morphology and metastable crystal lattice configurations that span a range between tetragonal structures and thermodynamically preferred orthorhombic structures. We find that the chemical stability of CsPbBr3 NRs is degraded by the presence of alkyl amines that etch CsPbBr3 and result in the formation of Cs4PbBr6 and 2-D bromoplumbates. Our study outlines strategies for maintaining metastable states of the soft lattices of perovskite nanocrystals undergoing exchange reactions, despite the thermodynamic driving force toward more stable lattice configurations during this disruptive chemical transformation. These strategies can be used to fine-tune the band gap of LHP-based nanostructures while preserving structure–property relationships that are contingent on metastable shapes and crystal configurations, aiding optoelectronic applications of these materials. [ABSTRACT FROM AUTHOR]

Perovskite/Silicon Tandem Solar Cells (PSTSCs) represent an emerging opportunity to compete with industry-standard single junction crystalline silicon (c-Si) solar cells. The maximum power conversion efficiency (PCE) of single junction cells is set by the Shockley–Queisser (SQ) limit (33.7%). However, tandem cells can expand this value to ~ 45% by utilising two stacked solar cells to harvest the solar spectrum more efficiently. 33.9% PCE has already been achieved with PSTSCs. This perspective analyses recent advances in PSTSC technology, with an emphasis on optimal perovskite composition, the problem and mitigation of light-induced halide phase segregation, self-assembled hole transporting monolayers and additives that can improve and stabilise the perovskite. Top-performing compositions show three cationic components (Cs+, FA+, Pb2+) and three anionic (I−, Br−, Cl−) with a bandgap between 1.55 and 1.77 eV and a theoretical maximum of 1.73 eV (717 nm). Anionic additives such as (Br3)− and SCN− reduce trap states and segregation. 2D-perovskite grain boundary interfaces are created with cationic alkylammonium additives such as methyl-phenethylammonium (MPEA) and result in improved performance. 2-, 3- or 4-terminal devices with a (partly) textured silicon heterojunction (SHJ) bottom cell are ideal. An ultra-thin interfacial recombination layer (~ 5 nm) of indium tin oxide (ITO) or indium zinc oxide (IZO) containing a carbazole-based hole transporting self-assembled monolayer (Me-4PACz) is used for optimal 2-terminal tandem devices. [ABSTRACT FROM AUTHOR]

Morphology plays a crucial role in defining the optical, electronic, and mechanical properties of halide perovskite microcrystals. Therefore, developing strategies that offer precise control over crystal morphology during the growth process is highly desirable. This work presents a simple scheme to simultaneously grow distinct geometries of cesium lead bromide (CsPbBr3) microcrystals, including microrods (MR), microplates (MP), and microspheres (MS), in a single chemical vapor deposition (CVD) experiment. By strategically adjusting precursor evaporation temperatures, flux density, and the substrate temperature, we surpass previous techniques by achieving simultaneous yet selective growth of multiple CsPbBr3 geometries at distinct positions on the same substrate. This fine growth control is attributed to the synergistic variation in fluid flow dynamics, precursor substrate distance, and temperature across the substrate, offering regions suitable for the growth of different morphologies. Pertinently, perovskite MR are grown at the top, while MP and MS are observed at the center and bottom regions of the substrate, respectively. Structural analysis reveals high crystallinity and an orthorhombic phase of the as-grown perovskite microcrystals, while persistent photonic lasing manifests their nonlinear optical characteristics, underpinning their potential application for next-generation photonic and optoelectronic devices.

Molecularly imprinted polymers with methylammonium lead halide perovskite quantum dots (MIP@MAPbBr3 PQDs) have been prepared and applied to the determination of benzo(a)pyrene (BaP) for the first time. The photoluminescence (PL) of MIP@MAPbBr3 PQDs was enhanced due to the surface passivation of defects by BaP. PL excitation and emission spectra, X-ray diffraction, Fourier transform infrared, and time-resolved PL studies suggest that the interaction between MIP@MAPbBr3 PQDs and BaP is a dynamic process. After MIP@MAPbBr3 PQDs were incubated with BaP, the benzene ring in the molecular structure of BaP can interact with MIP@MAPbBr3 PQDs through π electrons, which reduces non-radiative recombination of MIP@MAPbBr3 PQDs and lengthens excited state lifetime. The PL intensity of the MIP@MAPbBr3 PQDs-BaP system was monitored at 520 nm with 375 nm excitation. Under optimized conditions, the PL intensity of MIP@MAPbBr3 PQDs is linear with the concentration of BaP in the 10 to 100 ng·mL−1 range, with a detection limit of 1.6 ng·mL−1. The imprinting factor was 3.9, indicating excellent specificity of MIP@MAPbBr3 PQDs for BaP. The MIP@MAPbBr3 PQDs were subsequently applied to the PL analysis of BaP in sunflower seed oil, cured meat, and grilled fish samples, achieving recoveries from 79.3 to 107%, and relative standard deviations below 10%. This molecularly imprinted fluorescence assay improves the selectivity of BaP in complex mixtures and could be extended to other analytes. [ABSTRACT FROM AUTHOR]

A mixture of PbBr2 and YbBr3·nH2O in a dimethyl sulfoxide (DMSO) solution yielded single crystals of a lead halide perovskite precursor with ytterbium, bis[octakis(dimethyl sulfoxide)ytterbium(III)]pentabromidoplumbate(II) tribromide with dimethyl sulfoxide as co-crystallite, [Yb(C2H6OS)8][PbBr5]0.5Br1.5·0.5C2H6OS. The complex ions PbBr53− and Yb(DMSO)83+ are present in the crystal together with three Br− ions and DMSO molecules. X-ray crystallography revealed that the Br− ions in YbBr3 are replaced by the solvent and bound to a PbII atom or remain free. The presence of PbBr53− units, which are molecular ions with a square-pyramidal structure, is also observed. These single crystals react with a caesium chloride solution, exhibiting near-infrared (NIR) luminescence by visible photoexcitation, suggesting the formation of Yb3+-doped lead halide perovskites (CsPbBr3-xClx·Yb3+).

In recent years, the development of new efficient, fast, and intuitive materials and methods for photoluminescence (PL) sensing has become a research hotspot in analytical chemistry. Lead halide perovskite (LHP) materials have the characteristics of adjustable PL properties, high PL efficiency, and a variety of synthesis methods. Their PL is also sensitive to the change in specific factors in the environment. Based on these characteristics, LHP has shown good application prospects in the field of optical sensing. The study of the structural dimension, organic composition, or doped ions of LHP is helpful in exploring its sensing potential and proposing new sensing mechanisms, which have important research significance to promote sensing applications. In this review, the PL characteristics and sensing mechanisms, as well as their sensing applications of two- and three dimensional LHP, are discussed and summarized.

Perovskite photovoltaic has been attracting intense attention as an emerging technology due to its figure of merits including high power conversion efficiency, low-cost fabrication, and others. A successful commercialization of this type of technology has been significantly retarded by issues of elemental toxicity and device stability which are related to the key component of lead (Pb) in most efficient halide perovskites. Here, we first elucidated the origin of the superior optoelectronic properties of lead halide perovskites and their impact on photovoltaic device performance. We then discussed the promising approaches to solve the toxicity issue of lead hybrid perovskites. We further outlooked the effective solutions for lead hybrid perovskites for solar cell application. This review may provide a guidance for researchers interested in facilitating perovskite solar cells from exploitation to application.

Artificial chiral nanoparticles exhibit unique optical and (photo)physical properties. They can be all‐inorganic or organic–inorganic materials that are usually confined to the nanoscale by anchoring organic ligands to their surface. The ligands can also possess distinctive optical and/or (photo)physical properties, thereby adding functionality to the whole nanosystem and constituting an organic–inorganic nanohybrid. Development of luminescent chiral nanoparticles and nanohybrids is pertinent to many applications, such as (bio)sensing, therapeutics, photocatalysis, and optoelectronics, among others. This review deals with different photoactive nanomaterials, displaying either up‐shifting emission (nanoparticles consisting of a photoactive or inert matrix doped with lanthanides, Ln3+, upconversion nanoparticles, UCNPs) or down‐shifting emission, such as coinage metal nanoclusters (e.g., gold nanoclusters, AuNCs) and lead halide perovskite nanoparticles (HP NPs), as well as very low emissive nanoparticles, such as plasmonic nanoparticles (such as gold nanoparticles, AuNPs). Special attention is paid to the origin of the chiroptical response of these materials, showing that it is varied and can be alike for some of them. [ABSTRACT FROM AUTHOR]

Lead halide perovskite nanocrystals (LHPs) are emerging with enormous potential for high‐performance optoelectronics. Regrettably, most of the reported lead halide nanocrystal‐based photodetectors (LHP‐PDs) focus on six‐faceted hexahedron (cube/platelet) shapes and encounter issues of interface recombination of the photogenerated electron‐hole pairs and low carrier migration efficiency. Herein, a vertical heterojunction photodetector with type‐I band alignment based on high‐quality polyhedral orthorhombic CsPbBr3 nanocrystals (NCs) is designed and realized. The results show that utilizing these rhombic dodecahedron CsPbBr3 as photosensitive layers, the p‐Si/CsPbBr3 device presents high responsivity (R) and detectability (D*) values of 8.36 A W−1 and 9.33 × 1013 Jones, a powerful weak light detection capability with an ultralow noise equivalent power (NEP) of 2.14 × 10−15 W Hz−1/2, and a fast response time of 90/162 µs. Meanwhile, based on theoretical density functional theory (DFT) and energy band analysis, it is shown that the recombination of photogenerated electron‐hole pairs can be significantly suppressed, and the spectral response of the PDs is almost contributed by photogenerated carriers in CsPbBr3. The work provides a new avenue for improving the performance of PDs based on large‐size orthorhombic polyhedral CsPbBr3 NCs by morphological structure modulation and optimized band alignment engineering. [ABSTRACT FROM AUTHOR]

Transient photocurrent is a widely applied characterization technique to probe the charge‐carrier photogeneration and extraction dynamics in perovskite optoelectronic devices. Despite the large number of studies on the properties of perovskite single‐crystals (SCs) photodetectors (PDs), the underlying mechanism that governs the spectral line shape of transient photocurrent is not fully understood. Here, methylammonium lead bromide (MAPbBr3)SC based PDs are used to study the effect of different electrode spacing and bias on the transient photocurrent response under blue and green light irradiation. The observed differences in the spectral line shape of the transient photocurrent are explained using three‐step carrier transport model, which reveals the occurrence of carrier trapping and a recombination process in MAPbBr3 SC. The findings are further corroborated by intensity‐dependent photocurrent and impedance spectroscopy analysis of the resulting PDs. This work provides a basic insight into the origin of the different behavior of transient photocurrent response under variable electrode distance, bias, and irradiance light, which is expected to help to further understand and optimize the performance of perovskite based PDs. [ABSTRACT FROM AUTHOR]

Time-resolved photoluminescence (TRPL) has been extensively used to measure the carrier lifetime in lead halide perovskites. The TRPL curves of perovskite materials are usually fitted with a multi-exponential function, instead of a single exponential one. This was considered to be a result of the surface and the bulk recombination or the additional radiative recombination caused by the high excited carrier density. Here, a new model considering the diffusion and the trap-assisted recombination of carriers is proposed to explain the TRPL curves. The expressions of the TRPL curves and the transient absorption (TA) dynamic curves are theoretically derived, demonstrating that the TRPL curve is an infinite exponential series, regardless of the presence of surface recombination or not. Our newly developed highly sensitive nanosecond TA and TRPL were employed to measure the carrier dynamics of the same sample under low illumination in the linear response region of TA, thereby experimentally verifying our model. These results suggest that the decay of the TRPL is not only a consequence of the carrier recombination but also the carrier diffusion. TRPL cannot provide a direct measurement of the carrier lifetime, whereas TA spectroscopy can. Furthermore, the surface and the bulk recombination can be resolved and the average diffusion coefficient (D ¯) can also be correctly obtained by combining TRPL and TA measurements. We also propose an approximate method for calculating the carrier lifetime and diffusion coefficient of high-quality perovskite films. Our model provides not only a new interpretation of the dynamics of the PL decay but also a deep insight into the carrier dynamics in the nanosecond time scale under working condition of perovskites solar cells. [ABSTRACT FROM AUTHOR]

Copyright of Electronic Components & Materials is the property of Electronic Components & Materials 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.)

Abstract Transient photocurrent is a widely applied characterization technique to probe the charge‐carrier photogeneration and extraction dynamics in perovskite optoelectronic devices. Despite the large number of studies on the properties of perovskite single‐crystals (SCs) photodetectors (PDs), the underlying mechanism that governs the spectral line shape of transient photocurrent is not fully understood. Here, methylammonium lead bromide (MAPbBr3)SC based PDs are used to study the effect of different electrode spacing and bias on the transient photocurrent response under blue and green light irradiation. The observed differences in the spectral line shape of the transient photocurrent are explained using three‐step carrier transport model, which reveals the occurrence of carrier trapping and a recombination process in MAPbBr3 SC. The findings are further corroborated by intensity‐dependent photocurrent and impedance spectroscopy analysis of the resulting PDs. This work provides a basic insight into the origin of the different behavior of transient photocurrent response under variable electrode distance, bias, and irradiance light, which is expected to help to further understand and optimize the performance of perovskite based PDs.

Colloidal cesium lead halide perovskite nanocrystals exhibit unique photophysical properties including high quantum yields, tunable emission colors, and narrow photoluminescence spectra that have marked them as promising light emitters for applications in diverse photonic devices. Randomly oriented transition dipole moments have limited the light outcoupling efficiency of all isotropic light sources, including perovskites. In this report we design and synthesize deep blue emitting, quantum confined, perovskite nanoplates and analyze their optical properties by combining angular emission measurements with back focal plane imaging and correlating the results with physical characterization. By reducing the dimensions of the nanocrystals and depositing them face down onto a substrate by spin coating, we orient the average transition dipole moment of films into the plane of the substrate and improve the emission properties for light emitting applications. We then exploit the sensitivity of the perovskite electronic transitions to the dielectric environment at the interface between the crystal and their surroundings to reduce the angle between the average transition dipole moment and the surface to only 14° and maximize potential light emission efficiency. This tunability of the electronic transition that governs light emission in perovskites is unique and, coupled with their excellent photophysical properties, introduces a valuable method to extend the efficiencies and applications of perovskite based photonic devices beyond those based on current materials.

We report on theoretical investigations of a methylammonium lead halide perovskite system loaded with iron oxide and aluminum zinc oxide ( ZnO : Al / MAPbI 3 / Fe 2 O 3 ) as a potential photocatalyst. When excited with visible light, this heterostructure is demonstrated to achieve a high hydrogen production yield via a z-scheme photocatalysis mechanism. The Fe 2 O 3 : MAPbI 3 heterojunction plays the role of an electron donor, favoring the hydrogen evolution reaction (HER), and the ZnO : Al compound acts as a shield against ions, preventing the surface degradation of MAPbI 3 during the reaction, hence improving the charge transfer in the electrolyte. Moreover, our findings indicate that the ZnO : Al / MAPbI 3 heterostructure effectively enhances electrons/holes separation and reduces their recombination, which drastically improves the photocatalytic activity. Based on our calculations, our heterostructure yields a high hydrogen production rate, estimated to be 265.05   μ mol / g and 362.99   μ mol / g , respectively, for a neutral pH and an acidic pH of 5. These theoretical yield values are very promising and provide interesting inputs for the development of stable halide perovskites known for their superlative photocatalytic properties. [ABSTRACT FROM AUTHOR]

A mixture of PbBr2 and YbBr3ºnH2O in a dimethyl sulfoxide (DMSO) solution yielded single crystals of a lead halide perovskite precursor with ytterbium, bis[octakis(dimethyl sulfoxide)ytterbium(III)]pentabromidoplumbate(II) tribromide with dimethyl sulfoxide as co-crystallite, [Yb(C2H6OS)8][PbBr5]0.5- Br1.5º0.5C2H6OS. The complex ions PbBr53- and Yb(DMSO)83+ are present in the crystal together with three Br- ions and DMSO molecules. X-ray crystallography revealed that the Br- ions in YbBr3 are replaced by the solvent and bound to a PbII atom or remain free. The presence of PbBr53- units, which are molecular ions with a square-pyramidal structure, is also observed. These single crystals react with a caesium chloride solution, exhibiting near-infrared (NIR) luminescence by visible photoexcitation, suggesting the formation of Yb3+-doped lead halide perovskites (CsPbBr3-xClxºYb3+). [ABSTRACT FROM AUTHOR]

In this work, the thermostability of F- doped CsPbBr3 has been investigated through first principles calculations. Firstly, crystal structures of CsPbBr3-δFδ with different ratios of F- to Br- have been built. The influences substituting Br- by F- on the crystal structure, electronic band structure, absorption and the thermodynamic property has been investigated and presented. This substitution of Br- by F- could distinctly regulate and control the crystal structure, electronic band structure, thermal stability and the electron transfer process between the ligand ions and Pb2+. Electron transfer process and the thermostability were important for the performance of luminescence materials and CsPbBr3-δFδ with mixed Br- and F- as ligand ions of Pb2+ exhibited better thermal stability than that of CsPbBr3 and CsPbF3. The fluorinated perovskite materials could be a preferable choice for applying to luminescence materials. [ABSTRACT FROM AUTHOR]

A universal approach to calculating diffusion coefficients in lead halide perovskite single crystals, which have ionic and mixed ionic–electronic conductivity, is proposed. Using impedance spectroscopy, it is demonstrated how to model a non-ideal Warburg element and transmission line equivalent circuit to identify ionic diffusion in the material. The proposed method is applicable to samples of any thickness and electrical properties. Additionally, it is shown how to overcome the challenges of low-frequency impedance measurement and the non-ideal behavior of the elements through extrapolative modeling and approximation. [ABSTRACT FROM AUTHOR]

All-inorganic cesium lead halide (CsPbX 3 , X = Cl, Br, I) perovskite nanocrystals (NCs), as a super star in semiconductor luminescent materials, have manifested colossal prospects in the fields of optoelectronic and photovoltaic applications. However, some inherent limitations of CsPbX 3 perovskite NCs like poor long-term stability, low photoluminescence quantum yields typically in the violet and blue regions, and abundant halogen vacancy defects, severely restrict their commercial applications. Doping engineering represents an effective strategy for modulating the optoelectronic and photophysical properties of CsPbX 3 NCs and enhancing their structural stability, contributing to improving the performance and operational stability of CsPbX 3 NCs-based photovoltaic and optoelectronic devices. In this review, we summarize the latest advancements in metal ion-doped CsPbX 3 NCs, which covers from their controlled synthesis, optical properties design to various optoelectronic applications with a focus on solar cells and light-emitting diodes. Some future development directions and prospects of this vigorous research field are also proposed. Metal ion-doped lead halide perovskite nanocrystals have attracted extensive attention due to their exceptional optical properties and improved stability. In this review, we summarize the latest progress in the controlled synthesis of metal ions doped CsPbX 3 nanocrystals, emphasizing the effects of different metal ion doping on the optical properties, bandgap structure, stability, carrier behavior, and morphology of CsPbX 3 nanocrystals, as well as its significant advantages in improving the performance of optoelectronic devices. Current challenges and outlooks of perovskite nanocrystals toward commercial applications are also envisioned. [Display omitted] • The prevailing methods for synthesizing perovskite nanocrystals (NCs) are summarized. • The effect of metal ion doping on the optoelectronic properties of CsPbX 3 NCs is outlined. • Device engineering based on metal ion-doped CsPbX 3 NCs is highlighted. • Current challenges and future efforts toward perovskite materials and devices are put forward. [ABSTRACT FROM AUTHOR]

• Pe-CQDs are promising semiconducting materials for light-harvesting platforms. • Efficient Pe-CQD solar cells is achieved by surface chemistry and manipulation. • Pe-CQDs can be used in both solar cells and electroluminescent devices. • Multifunctional Pe-CQD solar cells can be employed for BIPVs. • This review highlights advancements in Pe-CQD solar cells and their multifunctionalities. Lead halide perovskites have emerged as a highly promising photoactive material for a wide range of optoelectronic applications, owing to their unique and outstanding optical, electrical, and optoelectronic properties. Particularly, lead halide perovskite colloidal quantum dots (Pe-CQDs), those synthesized with crystal sizes smaller than a Bohr radius, offer significant advantages over their bulk counterparts. These advantages include size-tunable optical bandgaps, suppressed scattering of visible light, solution-processible solidification without the need for thermal annealing, and the ability to form efficient cascade structures. Therefore, Pe-CQDs have garnered global prominence as a next-generation platform for reversible conversion of between light and electric energy in optoelectronic applications such as solar cells and light-emitting diodes (LEDs). In particular, Pe-CQD solar cells have revolutionized the field by achieving record-breaking power conversion efficiencies (PCE s) for CQD solar cells. However, the performance of Pe-CQD solar cells (the recorded PCE of 18.1 %) has not yet surpassed that of bulk perovskite solar cells (the recorded PCE of 26.1 %). This is because Pe-CQD absorbers, with their higher surface-to-volume ratio, exhibit significantly higher exposure of grain boundaries compared to bulk perovskite polycrystal absorbers. To further improve the performance of Pe-CQD solar cells, the surface defects arising from incomplete surface passivation at grain boundaries should be minimized. Therefore, it is necessary to understand the surface chemistry of Pe-CQDs and develop diverse strategies, including surface manipulation techniques. In this review, we demonstrate the remarkable advancements in Pe-CQD solar cells achieved by various surface manipulation and engineering strategies, encompassing surface ligand exchange and defect passivation methodologies. Furthermore, we critically evaluate selected studies that exemplify how morphological and structural manipulation strategies can enhance the device performance of Pe-CQD solar cells. Our focus centers on both Pe-CQD material design and its interplay with device physics. Additionally, based on the diverse advantages of Pe-CQDs, such as their semi-transparency, superior mechanical flexibility, and excellent electroluminescent properties, these materials hold great promise for various multi-functional Pe-CQD-based optoelectronic applications, including semi-transparent solar cells, flexible solar cells, and electroluminescent solar cells. [ABSTRACT FROM AUTHOR]

A feasible lead upcycling route is designed to recover lead halide products from lead smelting residues and use as raw materials for synthesis of FAPbBr 3-x I x perovskite for piezocatalytic hydrogen production. Zinc impurities from lead smelting residues further enhance the catalytic performance of FAPbBr 3-x I x. Our study offers a new possibility for green application and sustainable development of lead halide perovskite. [Display omitted] • Recovering lead halide products from lead smelting residues and use to synthetize FAPbBr 3-x I x perovskite pieocatalysts. • The FAPbBr 3-x I x pieocatalyst synthetized by the recovered lead halides achieve piezocatalytic HER activity of 157.80 μmol·g-1·h-1 under ultrasonic power of 112 W. • Zinc(Zn2+) impurities from lead smelting residues dope in structure of FAPbBr 3-x I x and further enhance the piezocatalytic performance. • Confirmed the feasibility of upcycling Pb from lead smelting residues to lead halide perovskite materials. Organic lead halide perovskite is a promising piezocatalyst for piezocatalytic H 2 production, meanwhile, large amount of unutilized lead resources in lead smelting residues have caused ecological security and resource waste problems. Here, we report an efficient Pb upcycling approach to recover lead halides from lead smelting residues to create lead halide perovskites (r-FAPbBr 3-x I x), distinguished by the remarkable piezoelectric properties, for piezocatalytic H 2 evolution. Zinc impurities, concurrently from these residues, found their utilization in the partial substitution of Pb2+ within the halide octahedra of r-FAPbBr 3-x I x. The intervention of zinc enhancing desorption of hydrogen from r-FAPbBr 3-x I x and culminating in a pronounced H 2 yield as 157.80 μmol·g−1·h−1. Notably, the used r-FAPbBr 3-x I x that lost its functional prowess could be regenerated and exhibited a piezocatalytic capacity similar to its initial state, perpetuating a sustainable cycle of utility. This pioneering route to Pb upcycling furnishes an alternative avenue for the preparation and utilization of lead-based perovskites. [ABSTRACT FROM AUTHOR]

Introduction: This paper deals with the class of versatile semiconducting materials called perovskites, which have been deposited for the first time on flexible substrates and then tested for radiation detection monitoring applications.Methods: Lead halide inorganic perovskite, CsPbCl3, 0.4–1 μm-thick films have been grown on plastic flexible substrates equipped with interdigitated electrodes (IDEs) by magnetron sputtering at room temperature.Results: First measurements in realtime configuration are reported for a 1–µm thick prototype under proton beams with energy in the range 100–228 MeV and 1–10 nA extraction currents, of interest for protontherapy applications.Discussion: Experimental results evidence good performances of our sample as a real-time monitoring device. Current stability under UV and proton beam exposure has been tested in the range 0.1–120 s, as well as reproducibility under multiple exposures. The measured current signal proved to be linearly dependent on the extraction currents at a given proton energy. Linearity of the current signal of the device with proton fluxes was also proved within two order of magnitude range, about 107–109 p/s. These promising results, when coupled with easyness of fabrication, low processing costs and high versatility of electrode configurations, all features characterizing the manufacturing process, put into evidence lead halide perovskites as promising candidates for real-time radiation detection in protontherapy.

Hybrid organic-inorganic perovskites play a critical role in modern optoelectronic applications, particularly as single photon sources due to their unusual bright ground state. However, the presence of trap states resulting from surface dangling bonds hinders their widespread commercial application. This work uses density functional theory (DFT) to study the effects of various passivating ligands and their binding sites on Rashba splitting, a phenomenon directly linked to the bright ground state. Our results predict that X2- and X4-type ligands that adsorb at acidic oxygen binding sites and zwitterionic binding sites efficiently eliminate trap states introduced by surface iodine vacancies. Furthermore, our results show that distortions from the nominally symmetric cubic structure of the perovskite predominantly determine the presence and magnitude of the Rashba splitting. Specifically, the loss of more symmetry elements consistently leads to Rashba splitting in both the valence band (VB) and the conduction band (CB) with small Rashba splitting coefficients. Conversely, although inversion symmetry breaking alone fails to guarantee the presence of pure Rashba splitting in both the VB and the CB, it significantly increases the degree of splitting. The adsorption of ligands not only mitigates trap states but also plays a critical role in altering the local symmetry, thus influencing Rashba splitting. DFT predicts a distinct Rashba-Dresselhaus splitting in the CB with X2 ligands, causing the largest splitting. The presence of local electric fields causes consistent Rashba splitting of the VB across all studied systems except for the X4 zwitterionic passivated systems (sulfobetaine and lecithin). Electric fields are predicted to cause significant splitting of the CB, particularly for MAPbI 3 and SH passivated MAPbI 3 surfaces that possess freely rotating ligand binding sites. This study reveals that the wavelength, tunability of Rashba splitting through an applied electric field, and nature of Rashba-Dresselhaus splitting are influenced by the characteristics of the ligand binding site. On the other hand, pure Rashba splitting is predicted to exhibit a greater susceptibility to symmetry distortion than to specific ligand binding sites. These findings elucidate how surface passivating ligands and symmetry distortions influence Rashba splitting, shaping the optoelectronic properties of perovskite nanocrystals.

Doping strategy in lead halide perovskites is essential to enhance its optoelectrical properties and expand the potential applications. In this work, the mechanisms, for how dopants affect the overall structural, optical, electrical, and chemical properties and stability of lead halide perovskite materials, are investigated. This is done by specifically considering various bismuth (Bi) doping concentrations in MAPbBr 3 single crystals grown using the inverse temperature crystallization method. The resultant doped single crystals exhibit a saturation point when Bi concentration exceeds 0.063% which is considered an optimum doping point. The highest thermal stability is also achieved at this doping concentration among the doped single crystals. This study clearly identifies how Bi doping affects the properties of MAPbBr 3 and extends to consider stability, which has not been fully considered for MA-based perovskites previously. This will provide a clear understanding of evaluating doped perovskite materials for enhanced material properties, device performance, and stability., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Producing heterostructures of cesium lead halide perovskites and metal-chalcogenides in the form of colloidal nanocrystals can improve their optical features and stability, and also govern the recombination of charge carriers. Herein, the synthesis of red-emitting CsPbI 3 /ZnSe nanoheterostructures is reported via an in situ hot injection method, which provides the crystallization conditions for both components, subsequently leading to heteroepitaxial growth. Steady-state absorption and photoluminescence studies alongside X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy analysis evidence on a type-I band alignment for CsPbI 3 /ZnSe nanoheterostructures, which exhibit photoluminescence quantum yield of 96% due to the effective passivation of surface defects, and an enhancement in carrier lifetime. Furthermore, the heterostructure growth of ZnSe domains leads to significant improvement in the stability of the CsPbI 3 nanocrystals under ambient conditions and against thermal and UV irradiation stress., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

The lead halide perovskite material shows its unique photoelectric properties, the resulting conversion efficiency of perovskite solar cells. However, the efficiency comes to a bottleneck owing to that mechanism research fall behind the device research. Multiple excitons dynamics play an important role, especially in the lifetime and binding energy of multiple excitons. A long multiexciton lifetime is beneficial to the application for light-emitting devices and photovoltaic devices. Large multiexciton binding energy means a large Stokes shift in exciton absorption, thus avoiding the loss of linear absorption. To conclude, discussions are presented regarding views of current multiple excitons research in terms of the biexciton lifetime and biexciton binding energy that should be considered for further advances in materials and devices.

In-depth and reliable characterization of advanced nanoparticles is crucial for revealing the origin of their unique features and for designing novel functional materials with tailored properties. Due to their small size, characterization beyond nanometric resolution, notably, by transmission electron microscopy (TEM) and associated techniques, is essential to provide meaningful information. Nevertheless, nanoparticles, especially those containing volatile elements or organic components, are sensitive to radiation damage. Here, using CsPbBr3 perovskite nanocrystals as an example, strategies to preserve the native structure of radiation-sensitive nanocrystals in high-resolution electron microscopy studies are presented. Atomic-resolution images obtained using graphene support films allow for a clear comparison with simulation results, showing that most CsPbBr3 nanocrystals are orthorhombic. Low-dose TEM reveals faceted nanocrystals with no in situ formed Pb crystallites, a feature observed in previous TEM studies that has been attributed to radiation damage. Cryo-electron microscopy further delays observable effects of radiation damage. Powder electron diffraction with a hybrid pixel direct electron detector confirms the domination of orthorhombic crystals. These results emphasize the importance of optimizing TEM grid preparation and of exploiting data collection strategies that impart minimum electron dose for revealing the true structure of radiation-sensitive nanocrystals.

The synthesis of CsPbX3 perovskite nanocrystals (NCs) has made remarkable progress with the growing demand for various optoelectronic applications. Obtaining CsPbX3 NCs through a detectable approach is a challenging topic. Herein, a noninjection synthesis strategy for CsPbX3 NCs with different morphologies is reported, which brings slow dynamics and simple operation. So, the evolution of NCs can be detected by spectroscopy, which is fundamental to understanding and manipulating the growth process. The nanocubes, nanowires, and encapsulated NCs obtained by this approach enable a broad range of future endeavors in display, laser arrays, and underwater optoelectronic devices, respectively. [ABSTRACT FROM AUTHOR]

Due to the tunable bandgaps, high quantum efficiency, and long carrier diffusion length, perovskites have attracted significant attention as active materials for solar cells, nanoscale lasers, photodetectors, and light‐emitting diodes. Herein, laser‐induced dual‐wavelength emissions from the CsPbBr3xI3(1–x) perovskite alloy microcrystals are reported. Under a 375 nm laser illumination, the micro‐photoluminescence (PL) emission spectra of these microcrystals exhibit two emission bands at 570 and 690 nm with gradually increased and decreased PL intensity, respectively. Moreover, the time‐dependent emission wavelength of the two emission bands almost has no changes, while the PL intensity of both emission bands shows periodic fluctuations with the on–off switching of excitation light. This dual‐wavelength emission phenomenon suggests that phase segregation occurs in these perovskite microcrystals during laser illumination. These results would provide valuable design guidelines for perovskites‐based tunable nanophotonic devices and multi‐color displays. [ABSTRACT FROM AUTHOR]

Doped perovskite lead halide nanocrystals (PHNCs) are promising materials for various optoelectronic applications, but the major challenge faced by the researchers is the inability to dope foreign elements into perovskite lattice because of the strong lead‐halide bond energies. In this work, we have used Fe as a dopant in CsPbCl3 to explore different doping techniques based on the colloidal synthesis of PHNCs to investigate the advantages and disadvantages of different techniques. We are able to dope a relatively higher amount of Fe (∼10%) than reported and observe clear optical signatures when the precursor does not have pre‐existing Pb−Cl bonds. We prove that there are two competing processes inside a doped PHNC – one is the effect of dopant energy levels, and the other is surface passivation by halide ions. Using the most optimal synthesis strategy, we show that although Fe does act as a luminescence quencher in perovskite similar to II–VI quantum dots (QDs), the quenching requires much more Fe compared to trace amounts of Fe required in traditional QDs. Our work will assist in giving an overall comparative idea of doping and finding the most optimized strategy and help identify the underlying physical processes in perovskite based QDs. [ABSTRACT FROM AUTHOR]

Lead halide perovskite nanocrystals (NCs) are extremely important as an absorber material for hot carrier (HC) solar cells. The extraction of the above‐bandgap excess energy of HC is essential to improve the device's performance. The fundamental understanding of the HC transfer process at the perovskite interface remains challenging. We have investigated the hot‐electron transfer dynamics at hybrid CsPbBr3/ thiol functionalized reduced graphene oxide (rGo−Ph−SH) using ultrafast transient absorption spectroscopy. Analysis reveals the significant drop in HC carrier temperature (from 1040 to 700 K) and HC cooling time (from 530 to 250 fs) in hybrid CsPbBr3/rGO−Ph−SH, suggesting the efficient hot electron transfer from CsPbBr3 NCs to surface anchored rGo−Ph−SH. We examine the HC relaxation mechanism using the electron‐longitudinal optical (LO) phonon coupling model and confirm the hot electron transfer. Here, we found that the hot‐electron transfer is three times faster than band‐edge electron transfer, with a maximum transfer efficiency of 43%. These findings shed new light on the study of the HC dynamics that could be beneficial for optoelectronic devices. [ABSTRACT FROM AUTHOR]

Abstract Passivation, as a classical surface treatment technique, has been widely accepted in start-of-the-art perovskite solar cells (PSCs) that can effectively modulate the electronic and chemical property of defective perovskite surface. The discovery of inorganic passivation compounds, such as oxysalts, has largely advanced the efficiency and lifetime of PSCs on account of its favorable electrical property and remarkable inherent stability, but a lack of deep understanding of how its local configuration affects the passivation effectiveness is a huge impediment for future interfacial molecular engineering. Here, we demonstrate the central-atom-dependent-passivation of oxysalt on perovskite surface, in which the central atoms of oxyacid anions dominate the interfacial oxygen-bridge strength. We revealed that the balance of local interactions between the central atoms of oxyacid anions (e.g., N, C, S, P, Si) and the metal cations on perovskite surface (e.g., Pb) generally determines the bond formation at oxysalt/perovskite interface, which can be understood by the bond order conservation principle. Silicate with less electronegative Si central atoms provides strong O-Pb motif and improved passivation effect, delivering a champion efficiency of 17.26% for CsPbI2Br solar cells. Our strategy is also universally effective in improving the device performance of several commonly used perovskite compositions.

Organo-lead halide perovskites have recently attracted great interest for potential applications in thin-film photovoltaics and optoelectronics. Herein, we present a protocol for the fabrication of this material via the low-pressure vapor assisted solution process (LP-VASP) method, which yields ~19% power conversion efficiency in planar heterojunction perovskite solar cells. First, we report the synthesis of methylammonium iodide (CH3NH3I) and methylammonium bromide (CH3NH3Br) from methylamine and the corresponding halide acid (HI or HBr). Then, we describe the fabrication of pinhole-free, continuous methylammonium-lead halide perovskite (CH3NH3PbX3 with X = I, Br, Cl and their mixture) films with the LP-VASP. This process is based on two steps: i) spin-coating of a homogenous layer of lead halide precursor onto a substrate, and ii) conversion of this layer to CH3NH3PbI3-xBrx by exposing the substrate to vapors of a mixture of CH3NH3I and CH3NH3Br at reduced pressure and 120 °C. Through slow diffusion of the methylammonium halide vapor into the lead halide precursor, we achieve slow and controlled growth of a continuous, pinhole-free perovskite film. The LP-VASP allows synthetic access to the full halide composition space in CH3NH3PbI3-xBrx with 0 ≤ x ≤ 3. Depending on the composition of the vapor phase, the bandgap can be tuned between 1.6 eV ≤ Eg ≤ 2.3 eV. In addition, by varying the composition of the halide precursor and of the vapor phase, we can also obtain CH3NH3PbI3-xClx. Films obtained from the LP-VASP are reproducible, phase pure as confirmed by X-ray diffraction measurements, and show high photoluminescence quantum yield. The process does not require the use of a glovebox.

Lead halide perovskite semiconductors have received significant attention in recent years as promising candidates for optoelectronic applications. Their controllable bandgap in nanostructures (nanocrystals, nanowires) has been widely and successfully investigated. Intentionally manipulating the atomic behavior with dopants in their macroscopic structure with high quality and stability is still challenging. We studied the crystal structure and photoluminescence (PL) behavior of the anion (Cl) doped CsPbBr 3 microcrystals. The doped microcrystal with a low doping concentration has shown a large wavelength-tunable PL emission from 535 nm to 457 nm. Two separate emission peaks (blue and green) are carefully studied in the excitation power dependent PL spectra. The doping and excitation endow the perovskite microcrystal adjustable PL emission band and peak intensities, which may serve as a new degree of manipulation freedom in the color-tunable display and functional optoelectronics. • The Cl doped CsPbBr 3 microcrystals with good stability have been synthesized by the hydrothermal antisolvent method. • The wavelength-tunable PL from green to blue emission bands was achieved by controlling the dopant concentration. • Excitation power dependent PL spectra indicate that the intensities of two emission have inhomogeneous trends. [ABSTRACT FROM AUTHOR]

• A unique perovskite photoelectrochemical cell was encapsulated using an inverted fluorine-doped tin oxide coated glass. • The 2D perovskite improved the water resistance and passivated the surface defects of the 3D perovskite. • The best photoanode achieved an outstanding long-term stability of 30.9 h (at t 90). Lead halide perovskites with excellent optoelectronic properties have been recognized as one of the most promising photoelectrode materials for photoelectrochemical water splitting during the past decade. However, fabricating stable and efficient halide-perovskite photoanodes remains a considerable challenge due to the degradation of halide perovskites in electrolyte environment and the lack of effective encapsulating techniques. Herein, we report a unique halide-perovskite photoelectrochemical cell by using an inverted fluorine-doped tin oxide coated glass (FTO/glass) as the waterproof hole-transport layer for encapsulation, and inserting a two-dimensional (2D) perovskite layer for passivation. The halide-perovskite photoanode achieves high-efficiency oxygen evolution reaction, fast bubble releasing and an outstanding long-term stability of 30.9 h at 90 % of the initial photocurrent density (up to 16.55 mA cm−2 at 1.23 V versus the reversible hydrogen electrode) under solar illumination. Our unique and cost-effective encapsulation method could be a potential solution for realizing stable and efficient halide-perovskite photoelectrodes for solar-fuel energy conversion. [ABSTRACT FROM AUTHOR]