Abstract
We report a series of fused pyrrolo[3,2-
d:4,5-
d′]bisthiazole (PBTz)-containing polymers as OPV donor materials, which exhibit a combination of small optical band gap, good solubility and relatively high molecular weight. The performance of the organic photovoltaic cells (OPV) made using the PBTz-containing polymers is studied. The highest performance was obtained with the polymer exhibiting the strongest crystallinity in the blend film, a PBTz-fused bithiophene polymer. Blend devices made from this polymer with PC
70BM delivered a short-circuit current density of up to 9.4
mA
cm
−2, an open-circuit voltage of 0.61
V, a fill factor of 53% and a power conversion efficiency of 3%.
► Fused pyrrolo[3,2-
d:4,5-
d′]bisthiazole (PBTz)-containing polymers as OPV donor materials. ► They exhibit small optical band gap, good solubility and high molecular weight. ► Strongest crystallinity leads to highest OPV performance. ► Best device delivered a
J
sc of 9.4
mA
cm
−2,
V
oc of 0.61
V, FF of 53% and PCE of 3%.