Impact of Rhodamine B solution on charge carrier generation and photocatalytic performance in CdS/TiO₂ heterostructures synthesized by CBD.

Abstract

This article presents the study of Rhodamine B solution effects on the generation of charge carriers and the photocatalytic performance of CdS/TiO2 heterostructure films. CdS/TiO2 heterostructure films were synthesized using the chemical bath deposition technique (CBD). The structure and morphology of the heterostructures were studied by X-ray diffraction (XRD), and Scanning Electron Microscope (SEM), respectively. The optical properties of the CdS/TiO2 heterostructures were characterized using a UV–vis spectrophotometer. The results showed that the CdS/TiO2 optical band gap energy (Eg) was 2.75 eV, between the TiO2 band gap energy (3.38 eV) and the CdS band gap energy (2.57 eV). The electrochemical characterization indicated that the photocurrent of the CdS/TiO2 heterostructure decreased from 29 mA to 12.4 mA when the UV-vis light source was turned off. The density of charge carriers generated on the surface of the CdS/TiO2 was simulated employing the WXAMPS software. The results suggest that the thickness of the TiO2 layer should be optimized to allow the activation of CdS. Finally, this study concludes that the presence of rhodamine B in the solution attenuates light transmission and affects the generated electron-hole pairs, resulting in poor photocatalytic behavior.