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CsPbBr3 nanoplates (NPs) have shown great potential in diverse optoelectronic applications. Despite the wonderful luminescence properties, the inherent instability of these NPs hinders their use in practical situations. Herein, a facile water‐assisted strategy is reported to synthesize highly stable blue emission CsPbBr3 NPs encapsulated in PbBr(OH). The introduction of water directly into the reaction mixture is pivotal, as it triggers the transformation of bulk CsPbBr3 nanocubes into 2‐D CsPbBr3 NPs within the PbBr(OH) matrix, resulting in the formation of CsPbBr3@PbBr(OH) microbricks. Remarkably, the water content in the reaction mixture allows the control of the number of perovskite layers in the NPs, thus enabling the emission color to be tuned from deep blue to green. The unconventional approach presented herein not only offers a cost‐effective pathway to synthesize blue‐emitting perovskites which are highly stable in a wide variety of polar and non‐polar solvents, but also holds immense potential for propelling the advancement of high‐performance LEDs and other optoelectronic devices. The findings underscore the significance of water in dictating the growth dynamics and emission characteristics of perovskite NPs, paving the way for their practical application. [ABSTRACT FROM AUTHOR]

Quantum‐confined perovskite CsPbBr3 Nanoplatelets (NPLs) have recently emerged as promising blue‐emitting materials for perovskite light‐emitting diodes (PeLEDs). Yet, their susceptibility to optical instability in solid films under ambient conditions poses a significant hindrance. This study introduces a novel chelating strategy that utilizes metal manganese ions and multidentate ligands, markedly improving the structural stability, and emission efficiency of NPLs. The approach involves adding Diethylenetriaminepentaacetic acid (DTPA) to the perovskite precursor solution, which allows for strong coordination to surface [PbBr6]4− octahedrons via its multiple chelation sites. Ensuing metal manganese ion integration during the purification phase addresses Pb2+ and Br− site vacancies, culminating in near‐perfect octahedral structures with significantly fewer vacancies. These metal manganese ions are then further immobilized on the NPLs surface by the chelating effect of unbound DTPA functional groups. The resultant CsPbBr3 NPLs films demonstrate an impressive PLQY of 66%, showcasing remarkable air stability with consistent blue emission for up to 5 days. The CsPbBr3 NPLs‐based PeLEDs show electroluminescence at 460 nm with a current efficiency of 1.07 cd A−1 and a maximum luminance of 220 cd m−2. The proposed chelating strategy positions perovskite NPLs as an extremely promising prospect in future applications of high‐definition displays and high‐quality lighting. [ABSTRACT FROM AUTHOR]

Recently, halide perovskite materials have shown great potential in photodetection due to their large light absorption coefficient and long carrier diffusion length. In contrast to the reported sandwich-structured devices and single-junction perovskite photodetectors, we demonstrate here a MAPbBr3/MAPbCl3 bulk heterostructure by splicing a MAPbBr3 single crystal and a MAPbCl3 single crystal. Interestingly, the photo-carriers generated from MAPbBr3 and MAPbCl3 can only be extracted when the device is forward and reverse biased, respectively. The capability to read out the photocurrents from the single crystals with different band gaps separately enables dual-band optical detection. In particular, the heterostructure photodetector exhibits a fast on–off switching time on the order of microseconds and peak responsivities of 17 mA W−1 at 450 nm and 7 mA W−1 at 355 nm, respectively. Dual-band photodetection is proved to be useful for dual-wavelength light communications. Our work provides a facile route to construct bulk heterostructures and the wavelength/bias-sensitive rectifier could provide guidance for optical communication modules in the future. [ABSTRACT FROM AUTHOR]

CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) have shown great potential in numerous applications including wide color gamut display and lighting. Despite the wonderful luminescence properties, the inherent instability of these NCs hinders their use in practical situations. Herein, we report a facile aqueous-based, ligand-free method to synthesize highly stable CsPbX3 NCs using ZIF-62, a metal–organic framework, as an encapsulation matrix which effectively isolates CsPbX3 from the surrounding. We discovered that the slightly alkaline nature of ZIF-62 facilitates the reaction between water and PbBr2 to form PbBr-(OH), which not only passivates the surface defects of the CsPbBr3 NCs but also prevents the perovskite from decomposing or oxidizing at high temperature. Sintering of ZIF-62 can therefore be performed in air at ∼300 °C to completely seal the perovskite within the insulating matrix, resulting in CsPbBr3/ZIF-62 composites exhibiting high stability against polar solvents, heat, light, and ambient humidity. Notably, the composite can maintain its bright luminescence without noticeable degradation in water for more than 2 months. The narrow-band emission and stability of these composites led to the demonstration of white light-emitting diodes with excellent color stability. Without the need for organic solvents during NC synthesis and noble gas ambient during sintering, the strategy proposed here can potentially facilitate the cost-effective, large-scale synthesis of highly stable perovskites which show great promise in commercial applications. [ABSTRACT FROM AUTHOR]

Filter‐free color imaging is the long‐pursued solution for its simple structure, low cost, and high stability. However, a spectroscopic unit is still necessary for the current Si‐based imaging unit due to the intrinsic photoresponse properties of Si. Here, the authors demonstrate a filter‐free color‐resolved single‐pixel imaging (SPI) by combining the working mechanism of computational ghost imaging and the response characteristic of perovskite. Benefitting from a broad linear dynamic range (106.5 dB) and a high detectivity (4.03 × 1014 Jones) of the fabricated ultrasensitive MAPbBr3 microwire arrays (MWAs) photodetector, the light attenuation caused by an object can be effectively correlated with its color. The reconstructed images of both transmissive and reflective color objects show a high wavelength resolution reaching 20 nm in the range of 400–540 nm, which is impossible to achieve by commercial silicon‐photodiode‐based ones. This work can open a new door for the image acquisition of color‐sensitive objects and also pave a way for the evolution of the next generation of detectors and cameras with low‐dimensional perovskite materials. [ABSTRACT FROM AUTHOR]

Metal halide perovskites (MHPs) have shown unparalleled potential for optoelectronic applications. In particular, the quasi one-dimensional perovskite structures have attracted great attention due to their unique optoelectronic properties which can open up new possibilities for this exciting materials system. However, it is challenging to acquire one-dimensional cubic-phase MHPs in high yield due to their isotropic crystallization nature and instability towards conventional fabrication processes. Here, we demonstrate the feasibility of synthesizing single-crystalline perovskite microwires from an intrinsic 1D structured lattice framework which defines the size and shape of the resulting microwires. By incorporating the appropriate monovalent ions into the lattice of self-assembled PbBr2 microwires, single-crystal CH3NH3PbBr3 microwires are successfully synthesized. The excellent crystal quality of the microwires has led to a high carrier mobility of 36 cm2 V−1 s−1 and a long charge carrier lifetime of ∼100 ns. As a preliminary demonstration of their optoelectronics functionality, single CH3NH3PbBr3 microwire-based photodetectors are fabricated and the devices exhibit a fast response time (a rise time of 113 μs and a decay time of 295 μs), stable light switching behavior, high sensitivity, and good spatial resolution. The method described here proposes a novel and facile strategy for synthesizing single-crystal perovskite microwires with high yield and repeatability, showing the great promise of MHPs in micro-optoelectronic applications. [ABSTRACT FROM AUTHOR]