Photoinduced Electron Transfer Processes in Dye-sensitized Solar Cells

Abstract

Electron injection processes in dye-sensitized solar cells have been studied. Transient absorption spectra were measured in a wide wavelength range (400—3000 nm) to probe photoproducts, oxidized dyes and conducting electrons. We estimated the efficiency of electron injection as a function of free energy change (ΔG)and found that surface of nanocrystalline films is energetically heterogeneous. Using a femtosecond spectrometer, we observed that electron injection occurs through several pathways, i.e., direct injection into the conduction band and injection via exciplex-like intermediates.