Dihydroindenofluorene–based polymeric donors incorporating structural isomers of pyrrolopyrroledione for non-fullerene organic solar cells.

In this study, we synthesized three new polymers, P1–P3, incorporating electron-donating 6,12-dihydro-6,6,12,12-tetraoctyl-indeno[1,2-b]fluorene (IF) and structural isomers of weak and strong electron-accepting 2,5-dioctyl-4,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,3(2H,5H)-dione (IFPPD) or 2,5-bis(2-ethylhexyl)-3,6-di(thiophen-2-yl)pyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione (LFPPD), or both the IFPPD and LFPPD units to study the performance of IF-based polymers on non-fullerene acceptor-based organic solar cells (NFA-OSCs). Polymer P1 exhibited absorption from 300 nm to 450 nm with an optical bandgap (Eg) of 2.39 eV, whereas P2 and P3 showed extended absorption up to 700 nm with an Egof 1.76 eV. The determined highest occupied molecular orbital/lowest occupied molecular orbital (HOMO/LUMO) levels for P1–P3 were −5.54 eV/–3.15 eV, −5.40 eV/–3.64 eV, and −5.42 eV/–3.66 eV, respectively. The NFA-OSCs fabricated using P1–P3 as the electron donor and Y6 as the electron acceptor exhibited a maximum power conversion efficiency (PCE) of 0.8%. We also utilized P1–P3 as a co-adsorber and fabricated ternary NFA-OSCs using P1–P3:PM6:Y6 blends. The performance of the ternary devices was lower than that of binary devices made from the PM6:Y6 blend. Herein, we report the preparation of IF-based polymers containing pyrrolopyrroledione derivatives for binary and ternary NFA-OSC applications. [ABSTRACT FROM AUTHOR]