Lead-Free All Inorganic Rubidium Copper Halide Rb2CuX3 (X = Cl, Br) for UVC Photodetector with Fast Response.

Abstract

Recently, lead halide perovskites have shown great potential in the photodetection field. Unfortunately, the existence of toxic lead elements restricts their practical application. Herein, high-quality 1D lead-free crystals Rb2CuX3 (X = Cl, Br) are successfully synthesized in an acidic medium. Rb2CuCl3 and Rb2CuBr3 display violet photoluminescence emission peaks at 401 and 388nm with a high exciton lifetime of 12.78 and 59.67µs, respectively, which is due to self-trapped excitons (STE). Furthermore, a photodetector is fabricated to detect harmful UVC radiation with Rb2CuBr3 as a light absorber. The proposed photodetector has a responsivity of 0.92mAW-1 and a specific detectivity of 1.57 × 109 Jones with a fast response speed of 2.67/2.70 µs for rise/fall time, respectively. In addition, both the samples show good stability against open air, and continuous ultraviolet light (254nm), as well as good thermal stability which is necessary for device fabrication. Thus, the present study suggests that stable, non-toxic, and environment-friendly Rb2CuX3 (X = Cl, Br) can be a promising candidate for future UVC optoelectronic devices.