Pulse electrodeposited zinc sulfide as an eco-friendly buffer layer for the cadmium-free thin-film solar cells

Zinc sulfide (ZnS) is an emerging alternate n-type buffer layer for the cadmium-free thin-film solar cells. The present research adopts a unique mixture of glycerol and tartaric acid for the emergence of phase-pure ZnS during pulse electrodeposition. Besides, proper optimization of pulse parameters aid in producing crystalline ZnS films with no post-deposition heat treatment. The as-deposited films exhibit cubic ZnS as confirmed from X-Ray Diffraction (XRD) and microRaman analyses. The optical study reveals an average transmittance of 71% in the wavelength spread of 300-900 nm with a band gap of 3.8 eV. The n-type semiconducting behavior of ZnS is affirmed from the Mott-Schottky analysis and the flat band potential is inferred to be -1.0 V vs SCE. The crystalline ZnS films produced from the economic pulse electrodeposition method devoid of heat treatment step, with their demonstration as photoanode in photoelectrochemical cells are suitable for the relevant applications.