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 nanocrystalline TiO2 solar cells are derived and verified by intensity-modulated photocurrent spectroscopy measurements. An exponential distribution of surface states can account for the observed power law dependence of the electron-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 distribution curve.