Thin films of Sb2S3 deposited by spray pyrolysis technique are characterized electrochemically and photoelectrochemically in a polyiodide electrolyte. The effect of substrates on the working of n-Sb2S3 thin film/polyiodide/C photoelectrochemical (PEC) solar cells has been investigated. The role of substrates like titanium, stainless steel and fluorine doped tin oxide (FTO)-pre-deposited glass slides on the Mott-Schottky plots is investigated at various (1 kHz and 100 Hz) frequencies and the reasons for the dispersion observed have been explained. Band edges of spray deposited Sb2S3 are located. Performance of the PEC cell is found to be improved on annealing and photoelectrochemical etching.