Influence of Cerium (Ce) Doping on the Optical Properties of Silver Sulphide (Ag2S) and Silver Sulphide (Ce: Ag2S) Thin Films Deposited by Electrodeposition Method

Thin Films of silver sulphide (Ag2S) have been successfully deposited onto FTO glass substrate using electrodeposition method to investigate the effects of Ce doping on Ag2S films. Silver trioxonitrate (V) and Sodium thiosulphate were the precursors used for silver and sulphur ions. Depositions of thin films made from cerium-doped silver sulphide were conducted at room temperature. Variations of percentage concentration of cerium dopant (2.5%, 5.0%, 7.5% and 10.0%) were considered in this paper. The optical properties of the thin films were characterized using Uv-Vis spectrometry. Absorbance results confirm that increasing Ce concentration significantly boosts the absorbance of Ag2S thin films, with the Ce: 10.0% film being the most effective in absorbing UV, visible, and near-infrared light, making it a promising material for applications in photovoltaics and optical devices, increasing Ce concentration results in reduced transmittance, making the films more absorptive, especially at higher concentrations, where Ce: 10.0% is the least transparent and most effective for applications requiring light absorption. Ce doping slightly increases the reflectance of Ag2S films, with higher Ce concentrations leading to higher reflectance, especially in the near-infrared region. This suggests that as Ce concentration increases, the films reflect more light, potentially reducing their effectiveness for absorption-based applications but increasing their suitability for applications where light reflection is desired. For extinction coefficient, the results revealed that the undoped Ag2S film shows the highest extinction coefficient, while doping with Ce generally reduces the extinction coefficient, with the 5.0% and 7.5% Ce-doped films exhibiting the lowest values. Other optical results were also presented.