Abstract
The energy density dependent fluorescence efficiency and fluorescence decay of neat films and solutions in 1,4-dioxane of poly[1,4-phenylene-1,2-di(4-phenoxyphenyl)vinylene] (DPOP-PPV), poly[1,4-phenylene-1,2-di(4-phenylthiophenyl)vinylene] (DPSP-PPV), poly[4,4'-diphenylene-1,2-di(4-phenoxyphenyl)vinylene] (DPOP-PDPV), and poly[4,4'-diphenylene-1,2-di(4-fluorophenyl)vinylene] (DFP-PDPV) are ...
Abstract
The energy density dependent fluorescence efficiency and fluorescence decay of neat films and solutions in 1,4-dioxane of poly[1,4-phenylene-1,2-di(4-phenoxyphenyl)vinylene] (DPOP-PPV), poly[1,4-phenylene-1,2-di(4-phenylthiophenyl)vinylene] (DPSP-PPV), poly[4,4'-diphenylene-1,2-di(4-phenoxyphenyl)vinylene] (DPOP-PDPV), and poly[4,4'-diphenylene-1,2-di(4-fluorophenyl)vinylene] (DFP-PDPV) are investigated with picosecond laser pulses. In low-concentration solutions, upon exciting more than one segment per polymer chain, the fluorescence efficiency reduces. In non-waveguiding thin neat films, the energy density dependent fluorescence signal reduction begins at much lower pulse energy density than in solution. The fluorescence behaviour is thought to be mainly due to exciton-exciton annihilation with time-dependent annihilation constant followed by polaron pair formation and subsequent polaron pair annihilation. (C) 2001 Elsevier Science B.V. All rights reserved.
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