Dependency of non-homogeneity energy dispersion on absorbance line-shape of luminescent polymers

Emission ellipsometry used to probe aggregation of the luminescent 2,1,3-benzothiadiazole dyes and ordering in an E7 liquid crystal matrix

“…Deconvolution of the spectra was performed with three Gaussian functions taken to represent the electronic transition (zero-phonon) and the first and second replicas (electron-vibrational coupling modes), where we used an effective vibrational mode for the C-C ring stretching of 125 meV. 14 Fig. 3b and c for 1A and 5A, respectively, show that the shifts in the experimentally-observed PL spectra are not reflected in the Gaussian curves; instead, there is an inversion in the relative contribution of the first and second emission bands.…”

“…The identification of J aggregates is difficult owing to the structural disorder at room temperature, as is the case of light-emitting polymers. 14 Such difficulty may be circumvented if nematic liquid crystals below the phase transition temperature are doped with p-conjugated luminescent dyes, because disorder would be decreased leading to a higher definition of the line shape of the spectra.…”

Kinetics of Thermal Conversion of Conjugated Polymers Investigated from Their Optical Absorption Spectra

“…5 The spectra were fitted with eq 2, with contribution from conjugated segments corresponding to n from 2 to 15 units 5 Figure 4 shows the results for all samples, in which contributions from conjugated segments with n > 6 were neglected because they represent only 5% of the spectra. Basically, the fitting is compatible with an average conjugation degree n c ≈ 3 for PPV and its derivatives, even though some of the polymer chains had 100 to 1000 units.…”

Decoupling Temperature–Volume Effects on Poly[2-Methoxy-5-(2′-Ethylhexyloxy)-1,4-Phenylene-Vinylene] Films at the β-Relaxation Temperature

“…The fitting of the photoluminescence (PL) spectra line shape was performed within the molecular exciton scope using the Franck–Condon principle for isolated molecules in homogeneous media and with the coupling of electron–vibrational modes parameterized by the Huang–Rhys parameters ( S j ). PL intensity I is calculated using the following equation , where ℏ is the reduced Plank constant, μ⃗ is the electronic transition moment, a m describes the medium effect, c is the speed of light, E g is the zero-phonon transition energy (energy difference between the lowest unoccupied molecular orbital and highest occupied molecular orbital), and d is the homogeneous energy dispersion (Gaussian distribution). G j *­( t ) in eq is given by where n̅ j = (exp­(ℏω j / k B T ) – 1) −1 , T is the sample temperature, and k B is the Boltzmann constant.…”

“…The fitting of the photoluminescence (PL) spectra line shape was performed within the molecular exciton scope using the Franck−Condon principle for isolated molecules in homogeneous media and with the coupling of electron−vibrational modes parameterized by the Huang− Rhys parameters (S j ). PL intensity I is calculated using the following equation 18,19 i k j j j j y…”