Quantifying the Relaxation Dynamics of Higher Electronic Excited States in Perylene.

Gating logical operations through high-lying electronic excited states presents opportunities for developing ultrafast, subnanometer computational devices. A lack of molecular systems with sufficiently long-lived higher excited states has hindered practical realization of such devices, but recent studies have reported intriguing photophysics from high-lying excited states of perylene. In this work, we use femtosecond spectroscopy supported by quantum chemical calculations to identify and quantify the relaxation dynamics of monomeric perylene's higher electronic excited states. The 2B state is accessed through single-photon absorption at 250 nm, while the optically dark 2A state is excited via the 1B state. Population of either state results in subpicosecond relaxation to the 1B state, and we quantify 2A and 2B state lifetimes of 340 and 530 fs, respectively. These lifetimes are significantly longer than the singlet fission time constant from the perylene 2B state, suggesting that the higher electronic states of perylene may be useful for gating logical operations.