| abstract |
Disclosed is a novel photosensitizer that can absorb light in a wide visible light region and in the case of a very thin film form, can enhance a light absorption efficiency by virtue of a large light absorption coefficient. The photosensitizer is used for metal oxide semiconductor electrodes and comprises a metal complex represented by a general formula ML 1 L 2 X 2 , wherein M is a group 8 transition metal of the periodic table, Xs are each independently a halogen atom, a cyano group, a thiocyanate group, an isothiocyanate group, an isocyanate group, an isocyanide group or a hydroxyl group, or a bidentate ligand in the case where Xs are bonded to one another, L 1 and L 2 are each a ligand having an aromatic ring, and either L 1 or L 2 has a functional group having a COOH group or PO(OH) 2 , and when the photosensitizer is adsorbed on a metal oxide semiconductor electrode via ligands L 1 and L 2 , the difference ΔL between the energy levels of ligands L 1 and L 2 in their excited states, calculated in accordance with a GAUSSIAN03 quantum chemistry calculation program is 0.25 eV or more. |