Synthesis and characterization of difluorophenazine-based conjugated polymers for organic photovoltaics

Abstract

Novel ACCEPTER units, difluorophenazine, were prepared and used for the synthesis of the conjugated polymers incorporating electron donor-acceptor pairs for organic photovoltaics. The introduction of a fluorine atom into the phenazine moiety led to a lowering of the highest occupied molecular orbital (HOMO) energy levels of the polymers. These acceptor units are likely to enhance electron transfer properties within the polymer structure. Conjugated polymers containing difluorophenazine, bithiophene and benzodithiophene, were synthesized using the Stille polymerization reaction to produce P1 and P2. The HOMO/LUMO energy levels of P1 and P2 were - 5.75/- 3.83 eV and - 5.81/- 3.78 eV, respectively. P2, which incorporates thiophene units into the benzodithiophene backbone, exhibits lower HOMO energy levels to increase the VOC Value. These energy levels are crucial for potentially enhancing the photovoltaic performance of the polymers.Graphical abstractNovel accepter units, difluorophenazine, were prepared and used for the synthesis of the conjugated polymers incorporating electron donor-acceptor pairs for organic photovoltaics. P2, which incorporates thiophene units into the benzodithiophene backbone, exhibits lower HOMO energy levels to increase the VOC Value