ABSTRACT
Dye-sensitized solar cells have been extensively investigated since M. Gratzel and co-workers reported a highly efficient solar-energy-to-electricity conversion efficiency of 10 per cent. A wide absorption range in the visible region for the coumarin dye is required to attain highly efficient solar-energy-to-electricity conversion. The wide absorption and red shift of absorption maximum in the visible region for photosensitizers is desirable for light harvesting of solar energy. The authors have synthesized new coumarin derivatives which are able to absorb visible light from 400 up to 700nm and prepared highly efficient dye-sensitized nanocrystalline Titanium dioxide (TiO2 ) solar cells using new coumarin photosensitizers. TiO2 thin films were prepared by screen printing on transparent conducting oxide (TCO) and then sintered at 500°C for 1 hour. Taking into consideration light absorption loss by TCO-coated glass, the light-to-current conversion efficiency is close to 100 per cent from 450 to 550nm.
