Self‐Filtered Narrowband Perovskite Photodetectors with Ultrafast and Tuned Spectral Response

Abstract Combining bandpass filters with broadband photodetectors is the most common way to detect light within a specific spectral range in many applications that need to detect only the light within desired spectral range. Here, a method is reported to realize narrowband spectral response of perovskite photodetectors by applying hybrid perovskites layers with the same or a slightly larger bandgap as filters, which are integrated into perovskite photodetectors. The narrowband photodetectors have a full width at half maximum of 28 nm due to the sharp absorption edges of perovskite materials, and the light rejection ratio is above 1000. By tuning the bandgaps of perovskite filters and the associated perovskite layers in the detectors, the response bands are continuously tuned in the whole visible light region to satisfy different applications. Superior to the thick single crystal narrowband perovskite photodetectors, the naorrowband peroskite detectors with this design have a very high response speed only limited by the resistance capacitance constant.