Franck-Condon analysis of fluorescence quenching in hybrid P3HT: wt% TBPO-capped CdSe quantum dot matrix

Fluorescence and optical absorption spectra of hybrid material׳s structure [Poly (3-hexylthiophene-2, 5-diyl) - wt% TBPO-capped CdSe] are measured and analyzed by the Franck-Condon theory. Fluorescence spectra both in solution and in thin films show a monotonic decrease with the increase in the TBPO-capped CdSe quantum dots concentration. We have used the Franck-Condon analysis method to estimate the vibrational modes energy, the Huang-Rhys factor and the relaxation energy as a function of TBPO-capped CdSe quantum dots concentrations. We notice that the Franck-Condon model is fairly sufficient to describe the decrease in fluorescence intensity. The theoretical phonon energies of symmetric and anti-symmetric C=C, C-H, C-H out plane stretching modes were set up to be in good agreement with experimental data determined by Fourier transform infrared transmission spectroscopy for pristine P3HT film.