Grätzel solar cells consist of nanocrystalline dye sensitized TiO2 photovoltaic cells. Such cells contain a nanoporous surface of TiO2, which is a wide bandgap semiconductor. The light excites electrons from the dye which are then injected into the conduction band of the TiO2. This electrochemical process is regenerative, with part of the converted energy being lost due to charge recombination. Understanding this recombination process is an important step for the development of more efficient cells. We make a suggestion for an experiment for undergraduate physics laboratory classes using such solar cells and we show that the efficiency increases along with the growth of the value of the internal resistance of recombination.
solar energy; TiO2 solar cell; internal resistance
