Up-conversion of photon energy in colloidal clay systems

Abstract

The up-conversion (UC) of photon energy was attempted for the system of a colloidal clay dispersion through the mechanism of triplet-triplet annihilation. Tris(1,10-phenanthroline)ruthenium(II) ([Ru(phen)3]2+) and 9, 10-diphenylanthracne (DPA) were used as a donor and an acceptor, respectively. A used clay mineral was synthetic saponite. A medium was 1:1:0.1 (v/v) methanol/dichloromethane/water. Δ-[Ru(phen)3]2+ (4.9 × 10−5 M) was adsorbed by SAP (3.8 × 10−4 M) to 26% CEC. The dispersion was irradiated by a laser light (0.5 mW) at 450 nm in the presence of DPA (4.2 × 10−3 M). An emission with the peak around 430 nm was observed under air. It implied the Ru(II) complex adsorbed by a colloidal clay acted as a donor to achieve UC. Quantum yield of UC was estimated to be 0.009 ± 0.003. The effect of stereoselectivity was investigated when a chiral donor/acceptor pair was employed.