Self-filtering narrowband perovskite photodetector with ultra-narrowband and high spectral rejection ratio

Narrowband photodetectors have broad application prospects in many fields where only a range of specific wavelengths of light needs to be detected. However, the current narrowband detectors have some disadvantages, such as the integration is difficult, the full width at half-maximum is not narrow enough, and the spectral rejection ratio is not ideal (≤20). Here, we present a self-filtering photodetector based on MAPbX3 single crystals with a very narrow spectral response and a full width of 15 nm at half maximum. It also shows a high responsivity (∼100 mA/W) and a high spectral rejection ratio (∼300). What is more, the response spectrum can be tuned within a certain range (from 440 to 560 nm) by varying the halide composition and thus its bandgap. This provides a new design paradigm for self-filtering narrowband photodetectors.