New copolymer involving poly (9-vinylcarbazole) and Poly(9,9-dioctylfluorene-alt-benzothiadiazole) (F8BT) for optoelectronic devices: Synthesis, characterization and modeling

Mbarek Mohamed^*1, Alimi Kamel¹

¹ Unité de Recherche : Matériaux nouveaux et Dispositifs Electroniques Organiques (UR 11ES55)  Faculté des Sciences de Monastir, Université de Monastir-Tunisie.

^*Corresponding author: mohamedmbarek99@yahoo.fr

ABSTRACT

New donor-acceptor based copolymer incorporating PVK as electron donor molecule and F8BT as electron withdrawing one has been designed and synthesized for organic solar cells applications.

The grafting of F8BT was elucidated by IR, Raman spectroscopy. The photo-emissive properties of new copolymer were examined by the means of UV-VIS and photoluminescence measurements. The resulting copolymer exhibits original optical properties compared to the PVK and F8BT ones. The red shifting in PL and absorption spectra showing an extension of conjugation length. A complementary study using theoretical calculations based on density functional theory (DFT) and time-dependant density functional theory (TD-DFT) methods were performed to examine the results copolymers. Then, Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO) levels have been calculated in order to elucidate the intramolecular charge transfer (ICT) between the electron acceptor and the electron donor moieties and to establish the energetic diagrams of PVK-based copolymer. All results showed that this copolymer exhibit interesting photophysical properties and shows promising photovoltaic trends..                                                                                                   .