Synthesis And Properties Of Novel Organic Sensitizers Based On Indoline For Dye-Sensitized Solar Cells

The survival of humanity is inseparable from energy. As the rapid development of human society, the demand for energy is increasing. With the consumption of non-renewable fossil fuels and the resulting effects on environment, the development and utilization of new energy has become a world-wide hot issue. Solar energy is more likely to replace fossil fuels in the mass energy for their inexhaustible, safe and clean, low cost and without geographical restrictions. So exploring a good dye sensitizer is the key to effectively utilize the solar energy.In order to increasing photoelectric conversion efficiency of dye sensitized solar cells (DSSCs), the sensitizers with indoline as electron donor, cyanoacetic acid and 3-carboxymethyl rhodanine as electron acceptor were investigated. Beside, this dissertation introduced benzothiadiazole as an extra electron acceptor based on traditional sensitized dye, two novel metal-free organic dyes with D-A-π-A structure have been designed and synthesized.The photophysical electrochemical and photovoltaic properties of the indoline dyes have been studied in detail. Compared with the two electron acceptors, cyanoacetic acid with strong electron-withdrawing ability showed much better molar extinction coefficient due to increasing the process of intramolecular charge transfer (ICT). Its photoelectric conversion efficiency reached 7.5%. While the photoelectric conversion efficiency of rhodanine dye with a large conjugated system was lower to 1.08%. It was found that cyanoacetic acid can efficiently inject electron into TiO2 film, but rhodanine can much less inject electron onto TiO2 due to the existence of unconjugated methylene group in the rhodanine unit. This indicated that band-gap decreasing have both advantage and disadvantage.