High-performance of self-powered UV photodetector with long-term stability based on ZnO nanorods and an iodine-free quasi solid-state electrolyte

Abstract

Vertical zinc oxide nanorods (ZnO NRs) were grown on a fluorine-doped tin oxide coated glass substrate using a simple hydrothermal method. A novel iodine-free quasi solid-state electrolyte containing 1-methyl-3-propylimidazolium iodide, potassium iodide (KI) and poly(ethylene oxide) (PEO) was prepared. KI acted as a charge transfer auxiliary agent and PEO was used to solidify the liquid electrolyte. A self-powered photoelectrochemical cell type ultraviolet (UV) photodetector was fabricated, using ZnO NRs as the active photoanode and the quasi solid-state electrolyte as the electrolyte. The dependence of the photocurrent on the iodine-free quasi solid-state electrolyte containing different amounts of KI and PEO was investigated in detail. An optimal photocurrent can be obtained when the amount of KI and PEO was up to 0.03 g and 0.2 g, respectively, and the photodetector shows high responsivity (2.33 A W⁻¹) and high sensitivity (533). The performance of the self-powered UV photodetector showed no obvious decay four months later, which shows great stability.