Fast response, narrow-band photodetector based on MAPbI3-MAPbBr3 single crystal heterojunctions

Narrowband photodetectors exhibit considerable potential for high-resolution imaging and encrypted communication systems owing to their high spectral resolution capabilities. In this study, a composite perovskite single-crystal heterojunction (SCH) consisting of MAPbBr 3 and MAPbI 3 was fabricated by epitaxially growing MAPbI 3 on a MAPbBr 3 single crystal substrate. A carbon paste light-window electrode was applied to the MAPbI 3 surface following a spatially modulated electrode strategy. The resulting device demonstrates outstanding narrowband detection performance, featuring a full width at half maximum ( FWHM ) of 21 nm, a spectral rejection ratio ( SRR ) of 137, a specific detectivity of 1.24 × 10 11 Jones (cm Hz 1/2 W −1 ), a responsivity of 0.56 A W −1 , and a fast response time (34.86/42.81 μs). The exceptional narrowband detection capabilities of this single-crystal heterojunction device would broaden the application prospects of perovskite-based photodetectors in the field of optoelectronics.