Conjugated polymer consisting of benzothiadiazole and phenazine as donor materials for organic photovoltaics

• We synthesized PThBT and PThFQ as donor materials.
• The synthesized polymers showed good solubility and thermal stability.
• PThFQ formed face-on structure on substrate.
• The FF of the PThFQ was 22% higher than that of the PThBT.

Two new polymers, poly(thiophene-benzothiadiazole) (PThBT) and poly(thiophene-dibenzophenazine) (PThFQ), were successfully polymerized through a Stille coupling reaction. PThBT exhibited the formation of an ordered lamellar structure with conventional edge-on π-stacking. In contrast, the PThFQ backbones were oriented face-on relative to the substrate. For solar cells using a 1:6 ratio of PThFQ to PC71BM, the resulting Voc, Jsc, FF and PCE were 0.73 V, 3.4 mA/cm2, 30.5% and 0.76%, respectively. The value of the FF for PThFQ increased by 22% compared to PThBT due to the effects of the backbone planarity of the polymers and the face-on orientation.

Figure optionsDownload as PowerPoint slide