Improvement of dye sensitized solar cells by using ZnO nanostructured electrods

The idea of converting light into electricty or chemical fuel has aroused interests of mankind for centuries. Photovoltaic science and technology carries out works on the conversion of solar energy into electrical power and great strides are covered for many years. Dye-sensitized solar cells are leading members of the group of new generation photovoltaic cells, which use organic dyes in order to obtain electricity from sunlight. In this PhD study, synthesis and characterization of nanostructured zinc oxide (ZnO) coatings used as photoelectrode materials in dye-sensitized solar cells, was aimed. Nanostructured ZnO coatings with the content of nanoparticles, nanorods and nanopowders have obtained by three different solution based methods including sol-gel, hydrothermal growth and homogenous precipitation. A comprehensive and systematic study was carried out to examine the effects of production methods and parameters on the physical, optical and photovoltaic properties of coatings. Structural and crystallographic properties of ZnO coatings have examined by various characterization techniques. It is determined that all of the produced coatings have polycrystalline nature and contain characteristic peaks of ZnO wurtzite structure. After characterization process, photovoltaic performances of ZnO-based dye sensitized solar cells have measured. Production methods and parameters on the properties of ZnO nanostructures, and hence the performance of ZnO-based dye-sensitized solar cell has been found to be affected directly. Besides the many parameters that can affect the cell performance, increasing particle sizes and coating thicknesses with increasing precursor solution concentrations have led to a decrease of the cell efficiency because of ineffective dye adsorption with decreasing active surface area. It has been determined that ZnO thin film coating based dye sensitized solar cell with wrinkle network morphology produced from solution with 0,5 molarity have the highest energy conversion efficiency among the other coatings.