A high-performance self-powered UV imaging photodetector based on litchi-like WO3 hollow spheres

Abstract

The self-powered UV photodetector (UVPD) has been considered one of the developing trends of future wireless and independent operational needs owing to its characteristic of working without external power supply. In this work, litchi-like WO₃ hollow spheres (HSs) were facilely synthesized through a hydrothermal approach and systematically characterized through scanning electron microscopy, transmission electron microscopy, etc. Notably, the WO₃ HSs exhibited an average diameter of about 350 nm, and the litchi-like surface consisted of numerous nanoparticles. Subsequently, a UVPD based on the WO₃ HSs was successfully manufactured, which displayed a fast response time (42.1/96.9 ms) with a high responsivity of up to 3.68 mA W⁻¹ and a detectivity exceeding 3.47 × 10¹⁰ Jones at zero bias. In addition, the as-prepared photodetector exhibited outstanding temporal stability after storage for 2 weeks in air together with multicycle reliability verified by processing 500 cycles with 96.4% maintenance of the initial photocurrent. Moreover, a high-quality image of “H, I, T” was distinctly obtained by applying the UVPD as a single-point sensing pixel to an imaging system.