Photoelectrochemical investigations of cadmium sulfide-doped silver (CdS) on flexible substrates

In this work, the chemical spraying pyrolysis (CSP) technique was used to deposit thin film of cadmium sulfide (CdS) doped with silver (Ag) at different proportions of 1%, 3%, and 5% on flexible polyimide (PI) plastic substrates at 300 °C. The effect of silver doping on the photoelectrochemical, electrical, and structural properties of cadmium sulfide films was investigated. The thickness of all films was on the order of 220 nm. All the deposited films were characterized by X-ray diffraction (XRD) technique, atomic force microscopy (AFM), scanning electron microscope (SEM), Hall measurement, and photoelectrochemical cell (PEC). The X-ray diffraction results confirmed the proper phase formation of the cadmium sulfide structure. In addition, the X-ray diffraction findings displayed a hexagonal precious stone structure with a favored introduction along the (002) plane independent of silver -doping fixation. The crystalline grain size was varied between 22.74 nm and 75.6 nm with varying silver doping ratios. From the atomic force microscopy images, it was confirmed that the surfaces of the prepared films were obviously smooth. The evaluated root mean square (RMS) surface roughness of the CdS-Ag samples decreased as the silver doping increased. In addition, the scanning electron microscopy results confirm the increasing in the smoothness of the films with increasing the silver ratio. Furthermore, the Hall measurement reveals a significant increase in the carrier concentration value from 1.43 × 10¹⁶ to 62.32 × 10¹⁶ cm⁻³ with a mobility value in the range of 6.5–43.34 cm² (V·S)⁻¹ with increasing silver ratio. It was concluded from the experimental results that the effectiveness of cadmium sulfide samples increases when the doping silver ratio increases according to a study on photoelectrochemical cell parameter evaluations.