Monitoring the reactivity of oxide interfaces in dye solar cells with photocurrent imaging techniques

By partially dip-coating and processing the F:SnO 2 front contact so that a very thin layer of platinum or of ruthenium oxide is formed, a breakdown of solar cell efficiency is observed via photocurrent imaging techniques. This evidences that the front contact functions like a degenerate semiconductor which determines the cell photopotential. Modification of the TiO 2 nanosurface with ultra thin alternative oxide layers (ZnO, Al 2 O 3 ) affects both electron injection and reverse reaction and thus photoefficiency. ZnO- and Al 2 O 3 - modified TiO 2 interfaces show an increased rate of sensitizer degradation. This result emphasizes the role of interfacial sensitizer bonding for long-term stability. .