An Electrically Modulated Single‐Color/Dual‐Color Imaging Photodetector. Issue 24 (7th May 2020) - Li, Lin
Abstract: An electrically modulated single‐/dual‐color imaging photodetector with fast response speed is developed based on a small molecule (CO i 8DFIC)/perovskite (CH3 NH3 PbBr3 ) 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 ≈544 nm (visible region) and ≈920 nm (near‐infrared region), respectively, without any power supply. Its two peak responsivities are 0.16 A W −1 at ≈525 nm and 0.041 A W −1 at ≈860 nm with a fast response speed (≈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 ≈475 nm, showing a fast response speed (≈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. Abstract : A tunable dual‐color imaging photodetector with a fast response speed (≈10 2 ns) is developed by constructing a type‐I p–n heterojunction of CH3 NH3 PbBr3 /CO i 8DFIC. Dual‐color imaging can be switched to single‐color imaging by applying a small bias voltage.