Integrated synthesis and comprehensive characterization of TiO2/AgBi2S3 ternary thin films via SILAR method

AgBi₂S₃, a copious and innocuous ternary metal chalcogenide affiliated with the I-V-IV group of semiconductors, was synthesized. With an energy gap of 1.2eV, it closely matches the optimal 1.39eV for solar cell absorbers. Importantly, this chalcogenide exhibits a high absorption coefficient of 10⁵ cm^-1 at 600 nm. Using the successive ionic layer adsorption and reaction (SILAR) method; we deposited an AgBi₂S₃ thin film onto a titanium dioxide (TiO₂) thin film. Characterization techniques encompassed XRD, SEM, EDXS, UV-Vis, EIS, and PEC performance analyses. The resulting TiO₂/AgBi₂S₃ composite film ranged in thickness from 8 μm to 13 μm, with particle sizes spanning 20 nm-265 nm. Notably, the deposition of AgBi₂S₃ onto the TiO₂ film caused depreciation in the TiO₂ energy gap from 3.1eV to 1.7eV. Furthermore, it significantly enhanced the TiO₂ film's absorbance across the visible and near-infrared regions. Intriguingly, the TiO₂/AgBi₂S₃ composite film also exhibited discernible photoelectrochemical behavior.