Synthesis of the pyrrolo[3,2-b]pyrrole-based copolymer with enhanced open circuit voltage

A new accepter unit, pyrrolo[3,2-b]pyrrole-2,5-dione, was prepared and utilized for the synthesis of the conjugated polymer containing electron donor–acceptor pair for OPVs. Pyrrolo[3,2-b]pyrrole-2,5-dione unit, regioisomer of the known pyrrolo[3,4-c]pyrrole-1,4-dione, is originated from the structure of stable synthetic pigment. The new conjugated polymer with pyrrolo[3,2-b]pyrrole-2,5-dione, thiophene and carbazole was synthesized using Suzuki polymerization to generate P1. The solid thin film of P1 shows absorption band with maximum peaks at 374 and 548 nm, and the absorption onset at 679 nm, corresponding to band gap of 1.83 eV. The field-effect hole mobility of P1 is 2.2 × 10−5 cm2/Vs. The device based on the polymer:PCBM (1:2) blend without thermal treatment showed a VOC of 0.82 V, a JSC of 6.28 mA/cm2, and an FF of 0.39, giving a PCE of 2.00%.

Graphical abstractA new accepter unit, pyrrolo[3,2-b]pyrrole-2,5-dione, was prepared and utilized for the synthesis of the conjugated polymer containing electron donor–acceptor pair for OPVs. Pyrrolo[3,2-b]pyrrole-2,5-dione unit, regioisomer of the known pyrrolo[3,4-c]pyrrole-1,4-dione, is originated from the structure of stable synthetic pigment. The device based on the polymer:PCBM (1:2) blend without thermal treatment showed a VOC of 0.82 V, a JSC of 6.28 mA/cm2, and an FF of 0.39, giving a PCE of 2.00%.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The pyrrolo[3,2-b]pyrrole-2,5-dione was prepared and utilized for the synthesis of the conjugated polymer. ► Pyrrolo[3,2-b]pyrrole-2,5-dione unit is regioisomer of the known pyrrolo[3,4-c]pyrrole-1,4-dione. ► Pyrrolo[3,2-b]pyrrole-2,5-dione unit is originated from the structure of stable synthetic pigment. ► The device based on the polymer:PCBM (1:2) blend had PCE of 2.00%.