Enhanced charge separation in self-powered UV photodetectors via a solution-processed CuO nanoparticle interlayer at the PEDOS/ZnO heterojunction

In this study, a high-performance self-powered ultraviolet photodetector (UV PD) is demonstrated, which is fabricated through straightforward hydrothermal and electrochemical deposition techniques. The device features a p–n heterojunction structure composed of ZnO nanorods (NRs) as the n -type bottom layer, poly(3,4-ethylenedioxyselenophene) (PEDOS) as the p -type top layer, and copper oxide (CuO) nanoparticles (NPs) incorporated as a key intermediate layer. Under weak UV irradiation (365 nm, 0.32 mW/cm 2 ), the fabricated UV PD delivers outstanding self-powered performance, attaining a responsivity of 0.185 μA/W and a detectivity of 3.58 × 10⁹ Jones. The CuO NPs insertion layer is verified as the key contributor to device performance enhancement: the UV PD with the CuO NPs interlayer exhibits a responsivity higher than that of the device without the interlayer. This performance boost is attributed to the CuO NPs’ ability to optimize heterojunction quality-specifically; it facilitates carrier generation, transport, and separation while extending carrier lifetime, thus substantially enhancing the responsivity of the CuO NPs/ZnO/PEDOS self-powered UV PD. Additionally, the fabricated self-powered UV PD exhibits excellent multi-cycle stability and robust detection performance under different light intensities. With its high efficiency and low-cost fabrication process, this self-powered UV PD exhibits great potential for practical applications in UV sensing systems.