Self-Powered Photodetector Based on FTO/n-TiO₂/p-CuMnO₂ Transparent Thin Films

A self-powered photodetector with the FTO/n-TiO₂/p-CuMnO₂ configuration, representing the novelty of the work, was successfully achieved for the first time and presumes two steps: deposition of the n-type semiconductor (TiO₂) by the doctor blade method and of the p-type semiconductor (CuMnO₂) by the spin coating technique, respectively. Investigation techniques of the structural and morphological characteristics of the as-synthesized heterostructures, such as XRD, UV-VIS analysis, and SEM/EDX and AFM morphologies, were used. The I-t measurements of the photodetector showed that the responsivity in the self-powered mode was 2.84 × 10⁷ A W^-1 cm² and in the 1 V bias mode it was 1.82 × 10⁶ A W^-1 cm². Additionally, a self-powered current of 14.2 nA was generated under UV illumination with an intensity of 0.1 mW/cm². Furthermore, under illumination conditions, the response time (t_res) and the recovery time (t_rec) of the sensor exhibited a good response; thus, t_res = 7.30 s and t_rec = 0.4 s for the self-powered mode, and in the 1 V bias mode, these were t_res = 15.16 s and t_rec = 2.18 s. The above results show that the transparent heterojunction device of n-TiO₂/p-CuMnO₂ exhibited a self-powered ultraviolet photodetector with high sensitivity.