Synthesis and characterization of benzobisthiazole based polymers as donor materials for organic solar cells

Two conjugated polymers with (X-DADAD) n backbone and 2,6- or 4,8-linked benzobisthiazole (BBT) moieties were designed, synthesized and characterized as absorber materials in thin-film organic solar cells (OSCs). The 2,6-BBT polymer (P1) delivered enhanced short circuit densities and power conversion efficiencies in OSCs compared to devices based on 4,8-BBT polymer P2. Improved photovoltaic performance is related to the optimal morphology of P1/PC 71 BM blend films and higher and more balanced charge carrier mobilities.