Photoexcitation and electron injection processes in azo dyes adsorbed on nanocrystalline TiO2 films

► Many azo dyes were synthesized and adapted for the sensitizers of TiO2 nanoparticles. ► Photon-to-current conversion efficiency of photovoltaic cells was measured. ► Quantum yield for dyes-to-TiO2 electron injection differs from dye to dye. ► No dye with its LUMO level lies below the conduction band edge gives efficient cells.