Structural, optical, and photo-electrochemical properties of marygold-like CdSe_0.6Te_0.4 synthesized by electrochemical route

Cadmium seleno-telluride (CdSe_0.6Te_0.4) ternary thin films were deposited on stainless steel and fluorine doped tin oxide (FTO) glass substrates by potentiostatic mode at different deposition times. The effect of deposition times on different physico-chemical properties of CdSe _0.6Te_0.4 was investigated in detail. As-synthesized CdSe_0.6Te_0.4 thin films were characterized using X-ray diffraction (XRD), UV-vis spectroscopy, field emission scanning electron microscopy (FE-SEM), and contact angle measurements. XRD patterns revealed the formation of CdSe_0.6Te_0.4 with a hexagonal crystal structure. FE-SEM micrographs showed the formation of different nanostructures of CdSe_0.6Te_0.4 thin films deposited at different deposition times such as marigold-like and twisted khari-like morphologies. The light absorption path length of a photon increases in the marigold-like nanostructures and thus can participate in multiple scattering and absorption. This is beneficial for effective light harvesting and improvement in the power conversion efficiency of solar cells. The optical study showed a drastic variation of band gap of CdSe_0.6Te_0.4 with the deposition time. Further photovoltaic activity of CdSe_0.6Te_0.4 films was studied by forming the photoelectrochemical cell having CdSe _0.6Te_0.4/1 M (Na₂S+S+NaOH)/C cell configuration. The efficiency and fill factor of these PEC cells are found to be 0.70% and 0.85, respectively.