Stabilizing TiO₂/CsPbI₂Br Perovskite Buried Interface for All‐Inorganic Perovskite toward Highly Efficient Photodetectors

Abstract Inorganic perovskites hold immense promise for optoelectronic applications, but their performance is often hindered by defects and trap states introduced during solution‐based processing. This study demonstrates a facile approach to mitigate these challenges by employing in situ polyvinyl pyrrolidone (PVP) passivation during the hydrothermal growth of TiO 2 nanorods, improving the interface with CsPbI 2 Br (CPIB) perovskite. X‐ray diffraction analysis confirms the formation of TiO 2 nanorods with a crystallite size of ≈49 nm and low microstrain. The PVP passivation layer effectively suppresses nonradiative recombination, leading to a significant enhancement in photoluminescence intensity. Photodetectors fabricated using PVP‐treated TiO 2 /CPIB interfaces exhibit significantly faster response times, with a rise time of ≈11 ms and a decay time of ≈0.3 ms, compared to devices without PVP. This results in an impressive photoresponsivity of ≈0.9 mA W −1 and a detectivity of ≈10¹ 2 10 12 Jones. This work demonstrates a simple yet effective strategy for improving the performance of all‐inorganic perovskite‐based optoelectronic devices, paving the way for their future applications in high‐performance photodetectors, solar cells, and other optoelectronic devices.