Solution processed CuInS2/SnO2 heterojunction based self-powered photodetector for UV encrypted visible light communication

Abstract

A photodetector (PD) featuring dual-band detection capability and self-powering attributes is crucial for various applications in sensing, communication, and imaging. Here, we present a self-powered PD based on a solution-processed CuInS2/SnO2 heterojunction capable of detecting UV and visible light spectra. The CuInS2 layer was composed of ∼2nm-sized quantum dots (QDs) synthesized using the hot injection method, while the SnO2 layer was fabricated using a straightforward solgel technique. This self-powered PD displayed a significant spectral response across both ultraviolet (UV) (355nm) and visible light (532nm) ranges, all accomplished without the need for external bias. The PD demonstrates rapid detection, with rise and decay times of 125ms and 156ms for visible light and 85ms and 200ms for UV light, respectively, at a power level of 15mW. The PD achieved responsivity values of 10.66µA/W and 34.56µA/W for visible and UV light, respectively. The impressive capability for dual-band detection in both ultraviolet (UV) and visible light showcases the practical feasibility and utility of this device for self-powered photodetection and deciphering UV-encrypted visible light communication. Moreover, its straightforward solution-based processing attribute renders it valuable for the mass production of devices and technology.