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CPL‐active flexible materials with high luminescence dissymmetry factor (glum) and luminescent quantum yield are indispensable for 3D displays, wearable devices and so on. Perovskite has drawn much attention due to its fascinating photoelectric properties as well as its abundant applications. However, the existing strategies are inefficient in acquiring perovskite NCs with high glum. In this work, thermoregulated CPL‐active flexible polymer/perovskite hybrid materials with high glum by the creation of chiral photonic bandgap in polymer film with cholesteric domains using toluene as the dielectric media is reported. Based on selective CPL reflection, a satisfied CPL with a maximum glum of 0.6 is achieved. Importantly, the chiral photonic bandgap center of the polymer film can be easily tuned by thermal annealing at different temperatures to adapt various perovskite NCs with full‐spectral emission. The handedness of CPL of hybrid materials can be regulated with and without dielectric media. The presence of the flexible polymer makes hybrid materials a candidate to achieve patterned display applications. Additionally, the polymer/perovskite hybrid materials show excellent stability thanks to the encapsulation effect from polymers. This work provides a facile and general approach to induce adjustable CPL in the whole visible spectrum with high glum and photoluminescence quantum yield (PLQY). [ABSTRACT FROM AUTHOR]

All-inorganic perovskite quantum dots (APQDs) have emerged as excellent materials which have been widely used in numerous micro-nano photoelectric devices. However, resistive random access memory (RRAM) devices based on APQDs are relatively scarce. In this work, RRAM based on CsPbBr3 APQDs prepared by the solution processed method was fabricated at room temperature. The sandwich structure memory device shows high reproducibility, good data retention ability, and light assisted multilevel storage capability. The resistance ratio (ON/OFF) of the RRAM device between the high resistance state and the low resistance state reaches almost 107. Additionally, the device exhibits high performances under low power consumption—low reading voltage (−0.3 V) and operation voltage (−2.4 V/1.55 V). It is suggested that the connection and rupture of conducting filaments, which are formed by Br vacancies under an electric field, are responsible for the resistive switching effect. Our work provides an opportunity to develop the next generation high-performance and stable nonvolatile memory devices. [ABSTRACT FROM AUTHOR]

In this work, TiO 2 nanorod arrays (TiO 2 -NAs) were modified by CuInS 2 quantum dots (CuInS 2 QDs) on the surface of the nanorods. The resultant TiO 2 -CuInS 2 nanorod arrays (TiO 2 -CuInS 2 -NAs) were characterized by UV/Vis spectroscopy, transmission electronic microscopy (TEM), and X-ray diffraction (XRD). The TiO 2 -CuInS 2 -NAs were applied as scaffold for the preparation of organic-inorganic hybrid perovskite solar cells. In comparison with the solar cell devices based on TIO 2 -NAs, a significant improvement in the power conversion efficiency had been achieved and the highest efficiency was obtained as 11.7% (under 100 mW/cm 2 ) through the optimization of the growth time of QDs on nanorods. The improvement of the device performance could be attributed to the assistance of CuInS 2 QDs in the light harvesting as well as the facilitation of the electron injection from the perovskite to the TiO 2 scaffold. [ABSTRACT FROM AUTHOR]

The exceptional optical and electronic properties of metal halide perovskite make it the ideal newly coming optoelectronic materials. Compared to the record efficiency acquired in organic-inorganic hybrid perovskite LED, however, thin film CsPbBr 3 perovskite LED is rarely reported. The inferior performance of CsPbBr 3 thin film perovskite LED can be ascribed to its delocalization nature, weak exciton binding energy, low quantum efficiency and high leakage current. After comprehensive consideration of these factors, in this work, we first put forward a new method for fabrication of highly crystalline CsPbBr 3 thin film through powder synthesis, and further control its interfacial properties to obtain continuous and uniform emission layer. The developed CsPbBr 3 thin film perovskite LED exhibits greatly improved performance, with luminance as high as 10,700 cd m −2 and current efficiency of 2.9 cd A −1 . Therefore, the facile powder method and subsequent interfacial modulation will open up a new and promising avenue for the future thin film perovskite LED development. [ABSTRACT FROM AUTHOR]

The recent success of solar cells has witnessed the emergence of metal halide perovskites as an important class of optoelectronic materials. Even with the record efficiency and inspiring performance, lead based perovskites are criticized for its toxicity, raising concerns about the environmental pollution. The reported divalent and heterovalent metal substitution for Pb indicates unfavorable performance. The lead-containing perovskite exhibits the outstanding activity compared to lead-free analogues. It is speculated that the perovskite with mixed-metal cation is expected to enable the fabrication of efficient device and partially alleviate toxicity. For this reason, herein, we present the first synthesis of perovskite nanocrystals based on mixed-metal cation, and demonstrate the implementation of mixed-metal cation perovskite nanocrystals into LEDs for the first time. [ABSTRACT FROM AUTHOR]

Abstract Methylammonium lead halide perovskites have received substantial attention in the research photovoltaic communities, because of excellent optoelectronic properties, including long electron-hole diffusion distance, large absorption coefficients in the UV–Vis spectral region, low-cost, solution-based processing and low binding energy of exciton. However, the crystal defects of perovskite films such as pinholes, defect and grain boundaries lead to carrier capture, trapping and scattering, so that reduce carrier mobility in the channel, which has become the bottleneck of high device performance and limited the application in photo detection. Here we report a simple and straightforward strategy based on a multi-step annealing process, which can effectively improves the coverage, smoothness, uniformity and crystallinity by restraining defects of pinhole formation. The field-effect mobilities of perovskite photodetector treated by one-step (OS) direct annealing method at room temperature shows mobility as 0.256 (0.129) cm2V−1s−1 for holes (electrons), which increase to 2.32 (1.18) cm2V−1s−1 for that treated by muti-step (MS) annealing method. The latter exhibits high figure of merit as detectivity of 8.94 × 1011 Jones, a responsivity of 32 A/W and a short response time of 42 μs. Moreover, it shows better stability with polymethylmethacrylate film covered, which can maintain 90% of initial performance for 10 days in ambient air. These findings demonstrate that MS annealing methods is simple yet effective and feasible to prepared high-efficient perovskite based photo detectors. Highlights • As well-known, the crystal defects of perovskite films such as pinholes, defect and grain boundaries lead to carrier capture, trapping and scattering, so that reduce carrier mobility in the channel, which has become the bottleneck of high device performance and limited the application in optoelectric devices. • However, the most works focused on perovskite solar cells, ignoring other perovskite optoelectric devices, like phototransistors. • Here we report a simple and straightforward strategy based on a multi-step annealing process, which can effectively improves the coverage, smoothness, uniformity and crystallinity by restraining defects of pinhole formation. • The field-effect mobilities of perovskite photodetector treated by one-step (OS) direct annealing method at room temperature shows mobility as 0.256 (0.129) cm2V−1s−1 for holes (electrons), which increase to 2.32 (1.18) cm2V−1s−1 for that treated by muti-step (MS) annealing method. • The latter exhibits high figure of merit as detectivity of 8.94 × 1011 Jones, a responsivity of 32 A/W and a short response time of 42 μs. Moreover, it shows better stability with polymethylmethacrylate film covered, which can maintain 90% of initial performance for 10 days in ambient air. [ABSTRACT FROM AUTHOR]

Flexible semitransparent photodetectors based on perovskites provide merits in terms of light weight and bifacial advantages but suffer from poor stability. To simultaneously enhance the performance and stability of flexible perovskite photodetectors (PPDs), silver (Ag) nanoparticles are incorporated to improve the responsiveness through the surface plasmon resonance (SPR) effect in the bulk of perovskite layer, and block copolymer F68 is employed to increase the surface hydrophobicity of perovskite film to keep long-term stable devices. Ag@polyvinyl pyrrolidone (PVP) core shell structure enables the sufficiently enhanced film light absorption and device quantum efficiency following the SPR response curve, the amphiphilic F68 make the perovskite less vulnerable to humid ambient exposure. Moreover, the sputtered transparent indium tin oxide back electrode enables the double facial operability of our flexible self-powered photodetectors with a bifacial factor of 80% and improved stability as well. Addressing the poor responsiveness and instability issues extends the potential broad applications of our bifacial flexible perovskite photodetectors. [Display omitted] • Double-side operable flexible self-powered perovskite photodetector is prepared. • Ag NPs improve the performance of the perovskite photodetectors through SPR effect. • The F68 polymer improves the moisture stability of perovskite photodetector. • A bifacial factor of 80% is achieved on flexible perovskite photodetectors. [ABSTRACT FROM AUTHOR]