Utilizing zinc oxide nanorods/polyaniline heterojunction as a flexible self-powered ultraviolet photodetector

In the face of the impending energy crisis, developing photoelectronic devices with broadband activity and selfpowered characteristics are crucial. Hence, a flexible self-powered ultraviolet photodetector based on sandwiched layers of Zinc oxide nanorods (ZnO) and polyaniline network (Pani) between polyethylene terephthalate (PET) plates along with copper electrodes (PZH) has been fabricated and studied. I-V-T characteristics of the flexible device showed nonlinear rectifying behavior at different temperatures, the formation of an inhomogeneous Schottky contact in ZnO-Pani interface, and the Richardson constant of 30.4 A cm-2 K-2 which is attributed to the ZnO. I-V curves of the device under different directions of ultraviolet light illumination have exhibited nonlinear rectifying behavior, high contrast ratio, and short-circuit current at zero bias voltage which imply the self-powered nature. The PZH exhibited various favorable photoresponsivity (RPh), acceptable response speed, and high photocurrent under different directions and power densities of the UV light. The results showed RPh and rise time (tR) of the device improved about 30% under light illumination from the Pani side than that of opposite direction, while best fall time obtained under light illumination from the ZnO side. The long-term stability, significant photoresponse properties, and simultaneous improvement of tR, RPh and photocurrent; offer our flexible hand-made device as a reliable self-powered photodetector with the broad-wide application and optimal efficiency. Finally, the possible mechanism to improve device performance under two direction of the light illumination through applying a standard thermionic emission-diffusion model and energy band diagram was discussed in detail.