Abstract

When a dye adsorbed onto an inert surface at submonolayer concentrations is excited by a weak laser pulse, its fluorescence quantum yield is lower than that observed in dilute solution and its fluorescence decay is generally nonexponential [1], in consequence of excitation transport to and trapping by dye oligomers. These effects are appreciable even for adsorbed dye optical densities of ~ 10⁻³. At early times following excitation, the intermolecular energy transport is expected to be nondiffusive, as the excitation is initially circulated within localized dye clusters arising from statistical surface density variations [2]. At long times when the excitation density tends to uniformity, the energy transport becomes diffusive.

© 1984 Optical Society of America