Ultra-Narrowband Photodetector with High Responsivity Enabled by Integrating Monolayer J-Aggregate Organic Crystal with Graphene

Narrowband photodetection has great significance for full-color imaging and machine vision. The most common way to realize narrowband detection is to combine a bandpass filter with a broadband photodetector. Herein, an ultra-narrow bandwidth photodetector without bandpass filter based on the combination of a monolayer J-aggregate organic crystal with graphene is demonstrated. The monolayer PTCDI-C₁₃ J-aggregate organic crystal grown on h-BN substrate, which exhibits an absorption bandwidth of 10 nm, works as a light-absorption material for narrowband photodetection; and graphene provides a conducting channel for photo-induced carriers from the monolayer J-aggregate film. Thanks to the ultra-narrowband absorption of the monolayer PTCDI-C₁₃ J-aggregate organic crystal and the high mobility of graphene, an ultra-narrow spectral response of ≈13 nm and high responsivity of 1000 A W^-1 can be achieved in photoconductor mode. This design concept is generic for other J-aggregates with different absorption windows and provides a new method to fabricate highly responsive narrowband photodetector.