Realization of Self-Powered High-Performance Photodetection via Electrostatic Field Enhancement and Dark Current Suppression

Self-powered photodetectors (PDs) are particularly attractive in the construction of environmentally friendly and sustainable Internet of Things. Utilizing dual functions of PTFE of electrostatic field enhancement and dark current suppression, a high-performance self-powered ITO/PTFE/TiO2/GaN UV PD is developed herein. The introduction of PTFE not only significantly reduces the dark current, but also facilitates the separation of photogenerated carriers by coupling the internal electrostatic field at the PTFE/TiO2 interface with the built-in electric field of the TiO2/GaN heterojunction. With 0 V bias, the light-to-dark current (Ilight/Idark) ratio of the PD with PTFE is improved by 2297 times and the response time is faster by 1.69/2.96 times compared to the ITO/TiO2/GaN PD. In addition, a microstructured M-ITO/PTFE/TiO2/GaN PD with micrometer-sized cylindrical TiO2 arrays exhibits a high Ilight/Idark ratio of 3.65 x 105, a responsivity of 280.1 mA W-1, a high detectivity of 1.97 x 1013 Jones, and a response time of 4.3/3.0 ms under 360 nm illumination. Our strategy provides a promising way to develop high-performance self-powered PD. Self-powered UV photodetector composed of ITO/PTFE/TiO2/GaN is fabricated, which utilizes high resistivity of PTFE to suppress the dark current while also enhances the photocurrent through the coupling of the electrostatic field at PTFE/TiO2 interface and the built-in electric field of the TiO2/GaN heterojunction, resulting in a 2297-fold increase in the light-to-dark current ratio compared to the ITO/TiO2/GaN photodetector.image (c) 2024 WILEY-VCH GmbH