title: Influence of excited-state absorption on time-resolved luminescence: general formalism and application to the phosphorescence of polycyclic aromatic hydrocarbons.
abstract: The luminescence decay of a species in an absorbing medium whose optical thickness changes with time, as occurs with triplet-triplet absorption following excitation cut-off, is studied theoretically and experimentally. A general luminescence decay function based on a distribution of optical thicknesses is presented. A simple decay function previously used empirically is shown to result from an exponential distribution of optical thicknesses. The general approach introduced allows the adequate description of the phosphorescence decays of two polycyclic aromatic hydrocarbons, coronene and triphenylene (normal and perdeuterated forms for both molecules), in polymer films in the presence of excited-state absorption.
authors.affiliation: CQFM-Centro de Química-Física Molecular and IN-Institute of Nanoscience and Nanotechnology, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa (Portugal).
authors.forename: Tiago
authors.initials: T
authors.lastname: Palmeira
authors.forename: Alexander
authors.initials: A
authors.lastname: Fedorov
authors.forename: Mário N
authors.initials: MN
authors.lastname: Berberan-Santos
keywords: coronene; luminescence reabsorption; phosphorescence; triphenylene; triplet-triplet absorption