Resonance Energy Transfer from the Lowest Excited Triplet State of Diphenylcarbene to Dye Molecules: Utilization for the Characterization of the Triplet−Triplet Fluorescence

Abstract

Triplet−triplet (T1 → T0) fluorescence spectra and decay curves of diphenylcarbene (DPC) in the absence and in the presence of dye molecules such as Rhodamine 6G and Rhodamine B were measured in several organic glasses at 77 K. In the absence of dye molecules, the T1 → T0 fluorescence signals exhibit biexponential decay with the lifetimes of ∼30 and ∼140 ns, which are attributable to the independent T1 → T0 emission from the individual T1 sublevels of DPC. In the presence of dye molecules, fluorescence decay signals of both fast and slow components were well analyzed in terms of resonance energy transfer of Forster type from DPC to dye molecule. The reaction scheme of the energy transfer and their various parameters are discussed on the basis of the independent T1 → T0 emission from the individual T1 sublevels of DPC at low temperature.