Efficient triplet exciton phosphorescence quenching from a rhenium monolayer on silicon

Abstract

We report efficient triplet exciton phosphorescence quenching from a Langmuir–Blodgett monolayer of a modified rhenium(I) fac-tricarbonyl bipyridine complex on the surface of crystalline silicon substrates indicating energy transfer. We monitor the luminescence quenching using phosphorescence lifetime imaging microscopy (PLIM) measurements as a function of distance of the monolayer to the silicon surface and have fitted the experimental phosphorescence lifetimes to a classical optical model. Our results show up to 95% phosphorescence quenching when the monolayer is close to the silicon surface (∼2 nm) indicative of efficient triplet resonance energy transfer from the rhenium monolayer to the silicon substrate. We believe this to be the first report of triplet sensitisation of silicon as a function of distance by a metal complex, and the most efficient triplet phosphorescence quenching from silicon reported to date.