Suppression of recombinations in a dye-sensitized photoelectrochemical cell made from a film of tin IV oxide crystallites coated with a thin layer ofaluminium oxide

A dye-sensitized photoelectrochemical cell consisting of a film of SnO2 cry stallites coated with ultrafine particles of Al2O3 generates an exceptional ly high open-circuit voltage as compared to a cell made only from SnO2. Al2 O3 coating on SnO2 improves the efficiency and the fill factor while delive ring reasonably high photocurrents. Photoexcited dye molecules on Al2O3 inj ects electrons into the conduction band of SnO2 via tunnelling through the Al2O3 barrier. Suppression of recombinations of electrons with the dye cati ons and the accepters at the electrolytic interface build up the quasi-Ferm i level in SnO2 with an impressive increase of the open-circuit voltage.