Effect of chelating reagents on nanostructured CdS layer morphology in CdS-sensitized TiO2 solar cells by successive ionic layer adsorption and reaction (SILAR) method

The chelating reagent is one of effecting factors which determines the properties of CdS films. Film morphology and roughness are very crucial in determining the further photovoltaic performance of the device. In this work, CdS film was synthesized by successive ionic layer adsorption and reaction (SILAR) method on FTO/TiO2 substrate. Different chelating reagents with N and S donating atoms were used in Cd2+ solution to investigate their effect on CdS film properties. X-ray diffraction spectroscopy (XRD), atomic force microscopy (AFM), ultraviolet-visible [1] spectroscopy, and Fourier transform infrared (FT-IR) spectroscopy were used for characterization of the films. Quantum dot-sensitized solar cells (QDSCs) were fabricated by using different produced photoanodes and the photocurrent density-voltage curves of the assembled solar cells were measured. Computational quantum chemistry methods were used for calculation of binding energy, topological properties between chelating reagents and CdS film. The HOMO and LUMO molecular orbitals were calculated and visualized. Experimental and theoretical results confirmed that the ligand containing S donating atom results in formation of CdS film with the lowest surface roughness and the highest photovoltaic conversion efficiency compared to the other ligands.