Influence of trap filling on photocurrent transients in polycrystalline TiO2

Abstract

Electron injection from optically excited dye molecules into the depletion layer of polycrystalline n-TiO2 electrodes is measured as photocurrent. The characteristic shape of the photocurrent transients has a point of inflection and is controlled by the complete filling of deep traps. The rate equations for the Shockley–Read trapping process are solved numerically for the case of high injection levels, and the shape of the transients is simulated.