Molecular relaxation temperature of poly (9.9-dioctylfluorenyl-2.7-diyl) using the Franck-Condon

作者：Longaresi R H^*; Marletta A; Faria G C; Faria R M

来源：Journal of Luminescence, 2016, 180: 117-122.

DOI：10.1016/j.jlumin.2016.07.067

• Franck-Condon analysis
• Poly(9.9-dioctylfluorenyl-2.7-diyl)
• Molecular relaxation
• Molecular aggregates

We report on the Franck-Condon analysis of temperature dependence emission spectra (140-340 K) of spin-carted poly(9.9-dioctylfluoreny1-2.7-diyl)(PF8) thin films. The photoluminescence spectra were analyzed considering the contribution of two species: isolates and aggregates. Results obtained from photoluminescence excitation and confocal spectroscopy measurements corroborate the hypothesis of two emitting species. FT-IR and Raman spectroscopy were used to obtain the effective electron vibrational modes for the isolate (700 cm(-1)) and aggregate (1250 cm(-1) and 1400 cm(-1)) species, providing values to be used in the Franck-Condon analysis. From the half maximum Gaussian bandwidth (Delta epsilon), we calculated an activation energy of approximately 250 meV for the inter-chain interaction (aggregates species), which were associated with the onset of movement on the polymer's side chain (beta-relaxation).

• 出版日期2016-12