High Spectral‐Rejection‐Ratio Narrowband Photodetectors Based on Perovskite Heterojunctions

Abstract Narrowband photodetection provides important information in a specific wavelength range. Specially, the use of nonoptical‐filter narrowband photodetectors based on MAPbX 3 (MA = CH 3 NH 3 ; X = Cl, Br, I) perovskites is reported of great potential. However, current MAPbX 3 ‐based narrowband photodetectors have to sacrifice their photocurrent and response speed to achieve an acceptable spectral rejection ratio. In this work, a new type of heterojunction photodetector (hetero‐PD) with a structure of (n‐type doped MAPbCl 3 )/(intrinsic MAPbBr 2.5 Cl 0.5 )/(n‐type doped MAPbBr 3 ) via epitaxial growth is demonstrated as a narrowband photodetector. Through optical bandgap engineering, photons with different wavelength can be absorbed in different layers. Owing to the n–i–n energy band structure,…