Synthesis and Characterisation of Photoanode Materials and Suitable Organic Dyes for Dye Sensitized Solar Cells

Abstract

Dye-sensitized solar cells are emerging alternative photovoltaic technologies compared to silicon-based and other thin-films-based solar cells. The advantages of DSSC are low cost, highly efficient, easy fabrication, eco-friendly and the performance of DSSC is not altered by climate, temperature, etc. Extensive research is going on for further improvement of DSSC performance without negotiating the low cost of commercialization. The main challenges in DSSC are absorption of light in the visible region and electron-hole recombination at the interfaces, which affects the charge carrier transportation. So the main objective of this thesis is focused to the improvement of efficiency of DSSC by reducing the charge recombinations and enhancing visible light absorption. DSSC components consist of semiconducting metal oxide (TiO2) as photoanode, inorganic (Ru-metal complex) dyes, LiI/I redox electrolyte and platinum counter electrodes. The research work is concentrated on photoanodes and sensitizers. newlineIn photoanodes, TiO2 plays a vital role in determining the performance of DSSC. TiO2 nanoparticles have a high surface area for higher adsorption of dye molecules hence for electron harvesting. However, some shortcomings in TiO2 are the charge recombination with dye and electrolytes. To avoid such complications, we have modified the TiO2 photoanodes by the effective way of doping with metals/non-metals. Ni and Cu (transition metals) and B (metalloids) have extensive consideration due to their good optical and electrical conductivity. In the present work undoped, Ni, Cu, B doped and Cu-Ni co-doped TiO2 nanoparticles are synthesized by sol-gel technique with different molar concentrations. The prepared nanoparticles are systematically analyzed by structural, morphological and optical properties. Further, the prepared nanoparticles are coated onto the FTO substrate via the Doctor-Blade technique to act as photoanodes, N719 sensitizers, LiI/I electrolyte and Pt counter electrode are utilized for the device fabrication.,