http://worldcat.org/entity/work/id/137219310

Fluorescence and phosphorescence of aromatic hydrocarbons in poly(methylmethacrylate) as a function of temperature

Fluorescence lifetimes (t) and fluorescence yields(P) of poly(methylmethacrylate) samples containing coronene-h12, coronene-d12, pyrene-h10, pyrene-d10, 1,2;5,6 dibenzanthracene, 1,2;7,8 dibenzanthracene, 1,2;3,4 dibenzanthracene, 1,2 benzcoronene and 1,12 benzperylene were measured. For all compounds studied, except coronene-h12 and coronene-d12, t decreases with increasing temperature. For all compounds except 1,12 benzperylene and 1,2;3,4 dibenzanthracene, P decreases proportionally with t so that the radiative lifetime (t) is temperature independent. For the two last mentioned compounds t varies with temperature. This may be due to the closeness of the p band to the lowest-lying alpha band. The activation energies of temperature dependent quenching of t are all similar. The quenching is related to Lin's theory of radiationless transitions and it is suggested that this temperature dependent quenching is due to S1 -- So transitions. (Author).

Open All Close All