A self-powered solar-blind photodetector with large Voc enhancing performance based on the PEDOT:PSS/Ga2O3 organic–inorganic hybrid heterojunction

Abstract

Self-powered photodetectors that can convert suitable light into an electrical signal without power supply are important and fundamental building blocks in the wide applications of environmental monitoring, light-wave communication, territory intrusions, and imaging technology. Motivated by the goals of fabricating a good-reliability, high-efficiency, and cost-efficient self-powered photodetector realizing zero power consumption, we construct an organic–inorganic hybrid photodetector with large open-circuit voltage (V_oc ≈ 0.9 V) based on the poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS)/Ga₂O₃ heterojunction. The prepared hybrid photodetector demonstrates a prominent self-powered photodetection performance with fantastic responsivity of 37.4 mA W⁻¹, superior detectivity of 9.2 × 10¹² Jones, and high external quantum efficiency of 18.3% at zero bias with 254 nm light illumination of 0.3 μW cm⁻². Under excitation of the 248 nm pulsed laser, the photodetector shows an ultrafast response speed with a rise time of 3.3 μs and decay time of 71.2 μs. Furthermore, the hybrid photodetector displays specific solar-blind spectrum selectivity with a high R_250nm/R_360nm rejection ratio of 7 × 10³ and good stability in ambient air even after one-week storage. The excellent photoelectric performance of the hybrid self-powered photodetector mainly profits from the efficient separation of photogenerated electron–hole pairs driven by the built-in electric field and the large photovoltaic effect (V_oc ≈ 0.9 V) of the PEDOT:PSS/Ga₂O₃ heterojunction. With the ability of harvesting photon energy from deep space to support the operation, this low-cost and high-performance self-powered photodetector will open potential applications in space exploration.