Synthesis and Characterization of Nanocrystalline TiO2 Thin Films for Use as Photoelectrodes in Dye Sensitized Solar Cell Application

Abstract

In the event of escalating gasoline prices resulting from threatened oil reserves and nuclear meltdowns endangering the quality of life in near future it is expected that science would make priceless contributions to green technology and come up with environment friendly solutions. Third generation photovoltaic solar cells have attracted researchers in this respect. Dye-sensitized solar cell (DSSC) is a novel category of economical photovoltaic cell that belongs to the group of thin film solar cells. The ability of developing and modifying nanoparticles has given scope to produce dye sensitized solar cells with a principle similar to that of photosynthesis. Promising efficiencies of around 11% have given scope for investment and advancement of this sector to get cheaper renewable solar energy available in abundance. The underlying principle uses a network of nanocrystalline TiO2 on a glass plate coated with transparent conducting oxide. Sensitization of nanocrystalline TiO2 network with dye enhances the efficiency of the cell. Nanocrystalline TiO2 has been synthesized by modifying titanium isopropoxide with diacetyl acetone, diacetyloxime and also by peptization with HNO3. The mean size of the particles is around 10–20 nm. Dip and spin coated electrodes (ITO glass substrate) with different thicknesses by multi layer deposition has been annealed at different temperatures. The deposited thin films are characterized by FTIR, UV-Vis and XRD for structural conformation, transmittance and phase confirmation respectively. Photovoltaic characterization has been done under dark condition to establish the semiconductor diode properties of the synthesized and modified TiO2 pastes using source meter, and model parameters have been evaluated by considering equivalent diode model for the solar cell.