This study presents the fabrication and characterization of a self-powered perovskite photodetector with a fast response time. We fabricated a RbCsMAFAPb(IBr)3 perovskite photodetector in an n-i-p planar architecture and systematically analyzed its performance. The device achieves an external quantum efficiency (EQE) exceeding 55% and a peak responsivity of 0.306 A/W at 730 nm. At the same wavelength, it demonstrates a detectivity of 1.183 × 10 9 Jones. With a rise time of 0.286 ms, the detector exhibits a competitive response speed among perovskite photodetectors. The device exhibited good stability over the course of 10 days. Furthermore, we investigated the incorporation of Al2O3 nanoparticles in the electron transport layer (ETL) and their impact on the morphology of the perovskite film.