Absorption spectrum and decay kinetics of triplet pentacene in solution, studied by flash photolysis

Abstract

The absorption spectrum of triplet pentacene in benzene and cyclohexane was determined at 50°C and assignments of the peaks were made. A kinetic study of the triplet absorption showed that the triplet decays by three competing processes: (1) a temperature-independent (between –96 and +50°C) radiationless transition to the ground state, (2) a triplet-triplet quenching process of low efficiency, and (3) a reversible reaction with ground-state pentacene producing a transient compound assumed to be a pentacene dimer.