Photoexcited Porphyrins Functionalizing TiO2 and SnO2 Nanocrystals

Porphyrins and metalloporphyrins on TiO2 and SnO2 play a leading role for the exploitation of solar energy. A way to increase the device efficiency may be the synthesis of well-organized porphyrin molecules, covalently anchored to the appropriate semiconductor surface. These covalent systems overcome the problem of loss of efficiency during the electron injection since the dye layer is directly in contact (covalent) with the semiconductor surface. In the present study, we show the synthesis, structure, and optical properties of a monolayer of a porphyrin and its copper complex covalently assembled on TiO2 and SnO2 powders. The porphyrin-functionalized TiO2 and SnO2 nanocrystals show luminescence quenching that is strongly dependent on the oxide substrates.