Zhi-Xiang Zhang, Chen Li, Yu Lu, Xiao-Wei Tong, Feng-Xia Liang,*, Xing-Yuan Zhao, Di Wu,Chao Xie, Lin-Bao Luo*

Abstract: In this work, we reported a sensitive deep ultraviolet (DUV) light photodetector based on inorganic and lead-free Cs3Cu2I5 crystalline film derived by a solution method. Optoelectronic analysis revealed that the device showed nearly no sensitivity to visible illumination with wavelength of 405 nm, but exhibited pronounced sensitivity to both DUV and UV light illumination with response speed of 26.2/49.9 ms for rise/fall time. The Ilight/Idark ratio was as high as 127. What is more, the responsivity and specific detectivity were as estimated to be 64.9 mA W-1 and 6.9×10¹¹ Jones, respectively. In addition, the device could retain its photoresponse 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 devise and systems.