Effect of etching and annealing on performance of CdS nanostructures photoelectrochemical solar cells

Nanostructures of CdS in thin films form have been achieved via chemical bath deposition followed by wet chemical etching process. Studies have been made by using scanning electron microscopy (SEM), atomic force microscopy (AFM) and UVvis spectroscopy techniques. SEM study reveals that the length of nanowires increases upon increment of etching time. AFM image shows that annealing of the photoelectrode leads to the fusion of small crystallites, resulting in agglomeration. Optical absorption study shows the presence of direct transition and band gap energies are found to be 2.58, 2.43, 2.40 and 2.38 eV, respectively, for the as-deposited and annealed films. Photoelectrochemical (PEC) investigations are carried out using cell configuration as n-CdS/(1M NaOH + 1M Na2S + 1M S)/C. Performance of the PEC cell is found to be improved on annealing and wet chemical etching.