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

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 TiO₂ nanorods, improving the interface with CsPbI₂Br (CPIB) perovskite. X-ray diffraction analysis confirms the formation of TiO₂ 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 TiO₂/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 ≈10¹² 10¹² 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.