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In recent years, the record efficiency of perovskite solar cells (PSCs) has been updated from 9.7% to 20.1%. But for the issue of stability, which restricts the outdoor application of PSCs, study still remains blank. The issue of the degradation of perovskite and stability of the device should be addressed urgently to achieve the good reproducibility and long lifetime of PSCs with high conversion efficiency. Without the study on stability, the exciting achievements can not be transferred from laboratory to industry and outdoor applications. In order to improve the stability, basic understanding about the degradation process of PSCs in different conditions should be studied thoroughly. This review summarizes the recent study about the relationship of chemical stability of PSCs with environments (oxygen and moisture, UV light, solution process, and temperature etc.) and the corresponding possible solutions.

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Degradation of perovskite has been a big problem in all-solid-state perovskite solar cells, although many researchers mainly focus on the high efficiency of these solar cells. This paper studies the stability of CH 3 NH 3 PbI 3 films and finds that CH 3 NH 3 PbI 3 is sensitive to moisture. The degradation reaction is proposed according to UV-Vis spectra and XRD results. In order to improve the degradation of CH 3 NH 3 PbI 3 , we introduce aluminum oxide as a post-modification material into all-solid-state perovskite solar cells for the first time. UV-Vis spectra show that Al 2 O 3 modification could maintain the absorption of CH 3 NH 3 PbI 3 after degradation. XRD results reveal that Al 2 O 3 could protect perovskite from degradation. Moreover, the device post-modified by Al 2 O 3 has shown more brilliant stability than that without modification when exposed to moisture. EIS results and dark current illustrate that the modification increased interface resistance in the dark, indicating the restrained electron recombination process.

into visible light that are further captured and converted into electrical signals by a following photomultiplier. [7][8][9][10][11] Scintillators have been actively utilized for radiation detection applications in many fields, like nondestructive inspection, medical imaging, and space exploration. Scintillator-based X-ray detectors are advantageous in terms of cost and stability than direct X-ray detectors (a-Se), and the current market of X-ray detectors is dominated by scintillators.The light yield of scintillators, as one of the most important figures of merit, determines the X-ray conversion efficiency and detection contrast. Liu and co-workers reported the good X-ray imaging properties from CsPbBr 3 nanocrystals [8] and Zhang et al. evaluated the light yield for CsPbBr 3 nanocrystals as 21 000 photons per MeV. [11] Such value is still much lower than traditional scintillators like Lu 1.8 Y 0.2 SiO 5 -Ce (LYSO, 33 200 photons per MeV), [12] CsI-Tl (54 000 photons per MeV) [12] and Gd 2 O 2 S-Tb (GOS, 60 000 photons per MeV) [13] etc. The major reason is that the small Stokes shift and the self-absorption effect for lead halide perovskites would severely restrict the light outcoupling efficiency in films and crystals, which require large thickness for complete X-ray attenuations. For scintillators, large Stokes shift and high photoluminescence efficiency are required to obtain high scintillation light yield. The recently emerged self-trapped exciton emissions from low dimensional perovskites exhibit large stokes shift and high PLQY, and may provide efficient X-ray scintillations, but have scarcely been studied. [14][15][16] Another severe issue restricting the applications of lead halide perovskite scintillators is the toxicity of lead element. The ionic nature of halide perovskites and high solubility in water may seriously harm the human health as well as the environment. It is thus of great significance to find lead-free perovskites or halide scintillators.Here we present 1D structured Rb 2 CuBr 3 as one new member of scintillators with exceptionally high light yield. Rb 2 CuBr 3 is obtained by direct reaction between RbBr and CuBr with phase-purity, high quality, and good stability. Its 1D crystal structure and soft crystal lattice facilitate the formation of self-trapped exciton, which emits at 385 nm with a large Stokes shift of 85 nm (0.91 eV) and 98.6% photoluminescence quantum yield. The high emission efficiency, large Stokes shift, strong X-ray attenuation, and good spectrum matching with the photomultiplier tube (PMT) or silicon photomultiplier Scintillators are widely utilized for radiation detections in many fields, such as nondestructive inspection, medical imaging, and space exploration. Lead halide perovskite scintillators have recently received extensive research attention owing to their tunable emission wavelength, low detection limit, and ease of fabrication. However, the low light yields toward X-ray irradiation and the lead toxicity of these perovskites severely restricts their practical ...

Lead halide perovskites show excellent optoelectronic properties but are unsatisfactory in terms of stability and toxicity. Herein, bismuth (Bi)‐doped lead‐free inorganic perovskites Cs2SnCl6:Bi are reported as blue emissive phosphors. Upon Bi doping, the originally nonluminous Cs2SnCl6 exhibits a highly efficient deep‐blue emission at 455 nm, with a Stokes shift of 106 nm and a high photoluminescence quantum yield (PLQY) close to 80%. Hybrid density functional theory calculations suggest the preferred formation of [BiSn+VCl] defect complex, which is believed to be responsible for the optical absorption and the associated blue emission. The Cs2SnCl6:Bi also shows impressive thermal and water stability due to its inorganic nature and the formation of protective BiOCl layer. White light‐emitting diodes (LEDs) are constructed using Cs2SnCl6:Bi and commercial yellow phosphors combined with commercial UV LED chips, giving the Commission Internationale de I'Eclairage (CIE) color coordinates of (0.36, 0.37). This work represents a significant step toward the realization of highly efficient, stable, and environmentally benign next‐generation solid‐state lighting.

Antimony selenide is an emerging promising thin film photovoltaic material thanks to its binary composition, suitable bandgap, high absorption coefficient, inert grain boundaries and earth-abundant constituents. However, current devices produced from rapid thermal evaporation strategy suffer from low-quality film and unsatisfactory performance. Herein, we develop a vapor transport deposition technique to fabricate antimony selenide films, a technique that enables continuous and low-cost manufacturing of cadmium telluride solar cells. We improve the crystallinity of antimony selenide films and then successfully produce superstrate cadmium sulfide/antimony selenide solar cells with a certified power conversion efficiency of 7.6%, a net 2% improvement over previous 5.6% record of the same device configuration. We analyze the deep defects in antimony selenide solar cells, and find that the density of the dominant deep defects is reduced by one order of magnitude using vapor transport deposition process.

Circularly polarized light (CPL) detection is required in various fields such as drug screening, security surveillance and quantum optics. Conventionally, CPL photodetector needs the installation of optical elements, imposing difficulties for integrated and flexible devices. The established CPL detectors without optical elements rely on chiral organic semiconductor and metal metamaterials, but they suffer from extremely low responsivity. Organic-inorganic hybrid materials combine CPL-sensitive absorption induced by chiral organics and efficient charge transport of inorganic frameworks, providing an option for direct CPL detection. Here we report the CPL detector using chiral organic-inorganic hybrid perovskites, and obtain a device with responsivity of 797 mA W -1 , detectivity of 7.1 × 10 11 Jones, 3-dB frequency of 150 Hz and one-month stability, a competitive combined feature for circularly polarized light detection. Thanks to the solution processing, we further demonstrate flexible devices on polyethylene terephthalate substrate with comparable performance.