TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The semiconductor comprises metal oxide(s) chosen from titanium oxide, zinc oxide, niobium oxide, tungsten oxide, indium oxide, tin oxide, nickel oxide and zirconium oxide, preferably titanium oxide and zinc oxide, more preferably titanium oxide.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The binding group of dyes (A,B) is chosen from alcohol, amino, nitrile, thiocyanate, acetoacetonate, hydroxyquinolate, alizarin, barbituric acid, carboxylic acid, dicarboxylic acid, phosphoric acid, phosphinic acid, sulfonic acid and hydroxamic acid, preferably styryl or dehydrostyryl carboxylic acid. The chromophore is chosen from porphyrin dyes, porphyrazine dyes, phthalocyanine dyes, coumarin dyes, indoline dyes, rhodanine dyes, thiophene dyes, xanthene dyes e.g. rhodamine B, rose bengal, eosin and erythrosine, cyanine dyes e.g. quinocyanine and kryptocyanine, anthraquinone dyes, polycyclic quinone dyes, azo dyes, basic dyes e.g. phenosafranine, fog blue, thiosine and methylene blue, and coordination compounds containing metal atom chosen from ruthenium, rhenium and iridium, and pyridyl, bipyridyl and terpyridyl complexes, preferably porphyrin dyes, porphyrazine dyes, phthalocyanine dyes and coumarin dyes, more preferably porphyrin dyes. The molar ratio of dye (A) and dye (B) is 1.5:1-5:1, preferably 2:1-4:1, more preferably 3:1. At least one of dyes (A,B) comprises porphyrin chromophore. The dyes (A,B) are non-metallated porphyrins or porphyrins metallated with metal chosen from zinc, magnesium, nickel, copper, cobalt, iron, tin, ruthenium, cadmium, palladium and platinum, more preferably dye (A) is metallated porphyrin containing zinc and dye (B) is non-metallated porphyrin. Alternately, the dyes (A,B) are porphyrins comprising linker to the binding group in ( beta )-position of porphyrin. The linker group of dyes (A,B) is chosen from linear or branched 2-30C hydrocarbon chain. The linker group of dyes (A,B) is chosen from 2-12C aliphatic, (2-12C aliphatic) aryl optionally substituted by binding group(s), 1-6C alkyl and 2-12C aliphatic aryl, and 2-12C aliphatic (aryl) optionally substituted by binding groups and linear or branched aliphatic chain.