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Spectral Diffusion and Triplet Exciton Localization in an Organic Glass
Author(s) -
Jankowiak R.,
Ries B.,
Bässler H.
Publication year - 1984
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221240139
Subject(s) - exciton , phosphorescence , excitation , diffusion , monte carlo method , thermal diffusivity , spectral line , absorption (acoustics) , deposition (geology) , molecular physics , materials science , atomic physics , physics , condensed matter physics , chemistry , optics , fluorescence , thermodynamics , quantum mechanics , paleontology , statistics , mathematics , sediment , biology
Phosphorescence spectra of glassy 2‐bromonaphthalene films prepared by vapor deposition at 4.2 K are recorded under site‐selective excitation. The Stockes shift between absorption and emission origins gradually vanishes as the excitation energy is scanned across the inhomogeneouslybroadened profile of the T 1 ← S 0 OO transitionindicating a continuous decrease of the exciton diffusivity with exciton energy. The effect is rationalized in terms of stochastic hopping transport across a Gaussian density of states. A Monte Carlo computer simulation provides the basis for quantitative data interpretation. A criterion for excitonimmobilization is established.