Singlet oxygen generation in porous silicon with fullerenes

Abstract We have studied light‐induced processes in ultra‐thin porous silicon (por‐Si) impregnated with fullerene C₆₀. After insertion of C₆₀ molecules a photoluminescence (PL) is quenched for more than one order of magnitude. No additional EPR defects were detected under fullerene insertion as it was revealed in por‐Si powder. Under illumination in oxygen the PL intensity could be restored to nearly initial level or to yet more. Recovery degree was dependent on oxidation state of por‐Si before C₆₀ insertion. As was observed by ellipsometry a PL recovery is accompanied with oxidation of porous layer. Observed phenomenon is related with known ability of C₆₀ to produce singlet oxygen. We suppose that generation efficiency of fullerenes to produce singlet oxygen is enhanced by energy transfer from photoexcited nanocrystallites. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)