Interfacial charge recombination of Os(ii)–polypyridyl–resorcinol complex on oleic acid capped TiO2 surface: what determines the dynamics?

Abstract

Femtosecond transient absorption spectroscopic studies of an osmium(II)–polypyridyl–resorcinol complex, 1, on oleic acid capped TiO₂ have been carried out and the results have been compared with our previous studies on poly(vinyl)alcohol capped TiO₂. While on both these surfaces the complex exhibits a single exponential <120 fs injection, the back electron transfer reaction is slower on the oleic acid capped TiO₂ surface early on while it is faster on the same surface at longer times than on poly(vinyl)alcohol capped TiO₂. The probable origin of these disparate observations has been analyzed.