Solvothermal method has been used for the synthesis of nanoparticles of II-VI semiconductors. Steps involved in the synthesis and chemistry have been discussed.Thin films of the corresponding nanoparticles have been deposited by spray technique. The effect of electric-field and iodine incorporation on optical, structural and morphological properties of the films has been studied and process of nanostructures formation has been discussed. Thin films of TiO2 and ZnO have been used to fabricate the DSSCs. The cells with TiO2 have shown the maximum efficiency of ~ 7.4% . The effect of underlying layer and barrier layers to achieve ~7.4% efficiency has been studied. Dye cells with ZnO as photo-electrode shows the maximum efficiency of ~4.7% for nanorod morphology film. Solid state dye sensitized solar cells have been fabricated by replacing the liquid electrolyte and organic dye with nanocrystalline CdX and HgX thin film layers. When CdTe nanoparticles are used as sensitizer the cell yields an efficiency of ~1% and for CdSe the efficiency of 0.87% has been achieved. When CdTe and CdSe nanorods are used as sensitizer cell efficiencies of 1.8% and 1.3% have been obtained, respectively.