Effect of Surface Hydrolysis at Tin Dioxide Polycrystalline Thin Film Electrodes on Dye Sensitization Quantum Efficiency

Abstract
The quantum efficiency of dye sensitization at polycrystalline SnO2 thin films can reach a high value close to ϕ = 1 if determined immediately after preparation, however it slowly drops down to low values (ϕ ∼ 0.01) after inserting the electrode into aqueous electrolyte solutions. The quantum efficiency decay rate depends on the electrolyte composition. Capacitance and cyclic voltammetry measurements indicate the formation of an insulating layer. Auger‐ and IR‐reflection spectra have been used to identify this layer as a mixed oxide/hydroxide formed by hydrolysis of the surface oxide. This layer acts as an energy barrier for the injection current from the excited dye molecule thus decreasing the sensitization quantum efficiency.

This publication has 25 references indexed in Scilit: