Effect of the surface-state distribution on electron transport in dye-sensitized TiO2 solar cells: Nonlinear electron-transport kinetics

Analytical expressions describing electron transport in dye-sensitized nano crystalline TiO2 solar cells are derived and verified by intensity-modulate d photocurrent spectroscopy measurements. An exponential distribution of su rface states can account for the observed power law dependence of the elect ron-transport rate on the electron population, Use of an effective electron diffusion coefficient to describe the electron transport kinetics is found to be inadequate. A slope of 69 meV is inferred for the surface-state dist ribution curve.