Dye Sensitised Solar Cells
Artificial photosynthesis–absorption of a dye onto titania nanoparticles is the basis of energy generation via a process that mimics natural photosynthesis. The titania nanoparticles give a very large surface area onto which the dye is chemically fixed. The dye then absorbs light to generate a photoexcited state, a high energy state from which the photoexcited electron is injected into the conduction band of the titania. The oxidised dye is then regenerated, ie reduced, by the electrolyte. The electron then flows around the external circuit to complete its work.
The elements of a dye sensitised solar cell are indicated in Figure 1. There must be a transparent electrode, normally Indium Tin Oxide (ITO) on glass to allow light to interact with the dye. The dye is absorbed onto The nanocrystalline titanium dioxide must form a continuous, mesoporous network, to transport