Sensitive Deep Ultraviolet Photodetector and Image Sensor Composed of Inorganic Lead-Free Cs₃Cu₂I₅ Perovskite with Wide Bandgap

Abstract

In this work, a sensitive deep ultraviolet (DUV) light photodetector based on inorganic and lead-free Cs₃Cu₂I₅ crystalline film derived by a solution method was reported. Optoelectronic characterization revealed that the perovskite device exhibited nearly no sensitivity to visible illumination with wavelength of 405 nm but exhibited pronounced sensitivity to both DUV and UV light illumination with response speeds of 26.2/49.9 ms for rise/fall time. The <i>I</i>_light/<i>I</i>_dark ratio could reach 127. What is more, the responsivity and specific detectivity were calculated to be 64.9 mA W^-1 and 6.9 × 10¹¹ Jones, respectively. In addition, the device could keep its photoresponsivity after storage in air environment for a month. It is also found that the capability of Cs₃Cu₂I₅ crystalline film device can readily record still DUV image with acceptable resolution. The above results confirm that the DUV photodetector may hold great potential for future DUV optoelectronic device and systems.