Thin-film tin oxide (SnO2) thin film was prepared at different temperatures via aerosol-assisted chemical vapour deposition (AACVD) technique and the morphological, optical as well as electrical properties was investigated using X-ray diffraction, atomic force microscopy, UV-Vis spectroscopy and Mott-Schottky plot. The SnO2 thin film deposited at high temperature exhibited higher crystallinity, rougher surface, higher light absorption and greater free-carrier density in comparison to low temperature processed counterpart. The prepared thin films were employed as photoanode in photoelectrochemical (PEC) water splitting and as electron transporting layer (ETL) in P3HT:PC70BM based-organic solar cell. Interestingly, it was discovered that the photocurrent density of PEC cells based on high temperature (450 degrees C) processed SnO2 layer was about 27 mu A/cm(2) at 1.0 V, approximately five times higher than that of SnO2 layer prepared at low temperature (180 degrees C). On the other hand, low temperature-based SnO2 ETL was found to enhance the efficiency of organic solar cells by about six times in comparison to their high temperature based counterparts. The reasons of such phenomenon lay in the morphological, optical and electrical properties of the fabricated SnO2 layer which is thoroughly explained in this paper.