An Electrically Modulated Single-Color/Dual-Color Imaging Photodetector

An electrically modulated single-/dual-color imaging photodetector with fast response speed is developed based on a small molecule (CO(i)8DFIC)/perovskite (CH3NH3PbBr3) hybrid film. Owing to the type-I heterojunction, the device can facilely transform dual-color images to single-color images by applying a small bias voltage. The photodetector exhibits two distinct cut-off wavelengths at approximate to 544 nm (visible region) and approximate to 920 nm (near-infrared region), respectively, without any power supply. Its two peak responsivities are 0.16 A W-1 at approximate to 525 nm and 0.041 A W-1 at approximate to 860 nm with a fast response speed (approximate to 10(2) ns). Under 0.6 V bias, the photodetector can operate in a single-color mode with a peak responsivity of 0.09 A W-1 at approximate to 475 nm, showing a fast response speed (approximate to 10(2) ns). A physical model based on band energy theory is developed to illustrate the origin of the tunable single-/dual-color photodetection. This work will stimulate new approaches for developing solution-processed multifunctional photodetectors for imaging photodetection in complex circumstances.