Exploring the experimental photoluminescence, Raman and infrared responses and density functional theory results for TFB polymer

The density functional theory (DFT) simulation method has been highlighted in last years, due to its ability to predict optical, electronic and molecular properties of different materials, presenting good agreement with experimental results. In this work, we conducted a study of the structural and optical properties of the copolymer poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4′-( N -(4-sec-butylphenyl)diphenylamine)] (TFB) which appears with great emphasis in the literature being applied mainly as hole transporting and electron blocking layer in devices. Raman and FT-IR measurements were taken, and the obtained results were compared with those calculated via DFT method (DFT/B3LYP and 6–31g*). The comparison between experimental and DFT results were performed, and a good agreement between both results was observed, showing discrepancy lower than 7% for the vibrational peak positions, in energy. Also, photoluminescence (PL) measurements were performed at room and liquid nitrogen temperature. The PL spectra were reconstructed via Franck Condon, through the Huang-Rhys parameters, by using the vibrational modes obtained both experimentally and via DFT. This procedure allowed to determine the contribution of the different vibrational modes to the photoluminescence vibronic bands.