Recently, metal halide perovskites have attracted tremendous attention because of the unprecedented development in the research field of optoelectronic applications. Among the perovskites, all-inorganic halide perovskites (IHPs), especially the cesium lead halide type, show great potential for light-emitting devices because of their excellent optoelectronic properties, such as an ultrahigh photoluminescence quantum yield, high absorption coefficient, and large carrier mobility. Moreover, recent advancements have demonstrated that the extraordinary optical and electrical properties combined with a high chemical stability and facile synthesis make IHPs promising candidates for next-generation high-performance photodetectors (PDs) beyond lightemitting technologies. In this Review, the syntheses of IHPs with different forms, as well as their fundamental optical and electronic properties, are first summarized and compared. Thereafter, we focus on the recent progress of IHP-based PDs working with different wavelengths, covering the infrared, visible, ultraviolet, and gamma regions. Then, the challenges and opportunities facing the field of PDs based on IHPs are discussed. Finally, a brief outlook is given for the future development of IHP-based PDs.

Hydrogen interstitials are expected to be important in organic–inorganic hybrid perovskites; however, the characteristics and behaviors of hydrogen in perovskites remain poorly understood. Here, on the basis of density functional theory calculations, we quantitatively reported that both atomic and molecular hydrogen interstitials can form in hybrid MAPbI3 and MASnI3 perovskites. Whereas molecular hydrogen interstitial, H2, is chemically inert, atomic hydrogen interstitial, H i , serves as an electrically active negative-U defect. We identify high-density H i + as a significant origin of ionic conductivity in p-type MAPbI3 under the hydrogen-rich conditions, with the calculated activation energy being comparable to that measured in experiments. The highly diffusive H i + ions are expected to impact hysteresis, charge separation, device polarization, and photogenerated field-screening effect and consequently degrade the solar cell performance. We evaluated approaches for mitigating such detrimental effects and suggested that synthesizing the perovskites with slightly extra iodine addition or tin alloying can effectively suppress the concentration of H i +. Our results are important to understand the fundamental aspects of hydrogen in perovskites in general and offer valuable insight for further improving the performance of perovskite solar cells and other optoelectronic devices via defect engineering.

Metal halide perovskites have emerged as promising candidates for next-generation optoelectronic applications due to their high absorption coefficient, tunable bandgap, long carrier mobility, and facile solution processability. Besides these superb...

Organic-inorganic hybrid perovskites, which combine the advantages of superior optical and electronic properties and solution-processed manufacturing, have emerged as a new class of revolutionary optoelectronic devices with the potential for...