In recent years, Pb-free CsSnI₃ perovskite materials with excellent photoelectric properties as well as low toxicity are attracting much attention in photoelectric devices. However, deep level defects in CsSnI₃, such as high density of tin vacancies, structural deformation of SnI₆⁻ octahedra and oxidation of Sn²⁺ states, are the major challenge to achieve high-performance CsSnI₃-based photoelectric devices with good stability. In this work, defect passivation method is adopted to solve the above issues, and the ultra-stable and high-performance CsSnI₃ nanowires (NWs) photodetectors (PDs) are fabricated via incorporating 1-butyl-2,3-dimethylimidazolium chloride salt (BMIMCl) into perovskites. Through materials analysis and theoretical calculations, BMIM⁺ ions can effectively passivate the Sn-related defects and reduce the dark current of CsSnI₃ NW PDs. To further reduce the dark current of the devices, the polymethyl methacrylate is introduced, and finally, the dual passivated CsSnI₃ NWPDs show ultra-high performance with an ultra-low dark current of 2 × 10^–11 A, a responsivity of up to 0.237 A W⁻¹, a high detectivity of 1.18 × 10¹² Jones and a linear dynamic range of 180 dB. Furthermore, the unpackaged devices exhibit ultra-high stability in device performance after 60 days of storage in air (25 °C, 50% humidity), with the device performance remaining above 90%.

The scalable and low-cost room temperature (RT) synthesis for pure-iodine all-inorganic perovskite colloidal quantum dots (QDs) is a challenge due to the phase transition induced by thermal unequilibrium. Here, we introduce a direct RT strongly confined spontaneous crystallization strategy in a Cs-deficient reaction system without polar solvents for synthesizing stable pure-iodine all-inorganic tin-lead (Sn-Pb) alloyed perovskite colloidal QDs, which exhibit bright yellow luminescence. By tuning the ratio of Cs/Pb precursors, the size confinement effect and optical band gap of the resultant CsSn_xPb_1-xI₃ perovskite QDs can be well controlled. This strongly confined RT approach is universal for wider bandgap bromine- and chlorine-based all-inorganic and iodine-based hybrid perovskite QDs. The alloyed CsSn_0.09Pb_0.91I₃ QDs show superior yellow emission properties with prolonged carrier lifetime and significantly increased colloidal stability compared to the pristine CsPbI₃ QDs, which is enabled by strong size confinement, Sn²⁺ passivation and enhanced formation energy. These findings provide a RT size-stabilized synthesis pathway to achieve high-performance pure-iodine all-inorganic Sn-Pb mixed perovskite colloidal QDs for optoelectronic applications.

The carrier transport layer with reflection reduction morphology has attracted extensive attention for improving the utilization of light. Herein, we introduced single-layer hollow ZnO hemisphere arrays (ZHAs) behaving light trapping effect as the electron transport layer in perovskite photodetectors (PDs). The single-layer hollow ZHAs can not only reduce the reflection, but also widen the angle of the effective incident light and especially transfer the distribution of the optical field from the ZnO/FTO interface to the perovskite active layer confirmed by the 3D finite-difference time-domain simulation. These merits benefit for the generation, transport and separation of carriers, improving the light utilization efficiency. Finally, our optimized FTO/ZHA/CsPbBr₃/carbon structure PDs showed high self-powered performance with a linear dynamic range of 120.3 dB, a detectivity of 4.2 × 10¹² Jones, rise/fall time of 13/28 µs and the f_−3 dB of up to 28 kHz. Benefiting from the high device performance, the PD was demonstrated to the application in the directional transmission of encrypted files as the signal receiving port with super high accuracy. This work uniquely utilizes the features of high-performance self-powered perovskite PDs in optical communication, paving the path to wide applications of all-inorganic perovskite PDs.