Electronic excited state transport and trapping in disordered systems: Picosecond fluorescence mixing, transient grating, and probe pulse experiments

Abstract

A detailed experimental examination of the dynamics of energy transport and trapping in two component systems, using rhodamine 6G (R6G) as the donor and malachite green (MG) as the trap in both glycerol and ethanolsolvents, is presented. The experiments were performed using fluorescence mixing and ground state recovery techniques providing temporal resolution of ∼50 ps. Samples ranging from high trap‐low donor concentrations (the Förster limit) to the opposite regime of high donor and low trap concentrations, were studied. These results were compared with no adjustable parameters to the recent theoretical work of Loring, Andersen, and Fayer (LAF). The excellent agreement between theory and experiment over the entire donor‐trap concentration range confirms the theoretical results of LAF and yields a comprehensive description of excited‐state dynamics in solution. A variety of dynamic properties are calculated using the LAF theory and the measured parameters associated with R6G‐MG system.