TIME-RESOLVED SPECTRA OF AN INTRA-MOLECULAR EXCIPLEX

Abstract

The intramolecular exciplex formed from N,N-methylphenyl 2-ethyl-(2-naphthoyl)amine was studied by time-resolved emission spectroscopy using a cavity-dumped argon ion laser (wavelength, λ = 257.25 nm) and single-photon counting detection. The spectra, taken at several time delays after excitation, show that the excited amine (lifetime, τf = 1.78 ns) contributes to the exciplex formation. The excited naphthoate (τf = 7.98 ns) is the major species observed in the late-gated spectrum (31 ns after excitation), its lifetime being larger than that of the exciplex (τf = 4.27 ns). The results obtained are explained on the basis of the existence of a static quenching and a slow dynamic quenching. © 1..