Pyrrolopyrrole-1,3-dione-Based Wide Band-Gap Polymeric Donors Exemplify High Voltage and Diminutive Energy Loss for Efficient Binary and Tandem Nonfullerene Organic Solar Cells with Efficiency Exceeding 15.7%

Here, the potential of pyrrolo[3,4-c]pyrrole-1,3-(2H,5H)-dione-based polymers, namely, poly[4,8-bis(5-(2-ethylhexypthiophen-2-yebenzo [1,2-b:4,5-b'] dithiophene-alt-2,5-dioctyl-4,6-di(thiophen-2-yl)pyrrolo [3,4-c] pyrrole- 1,3 (2H,SH)dione) (PBDPD), is tested as an electron donor in nonfullerene electron acceptor-based organic solar cells (NFA OSCs). Polymer PBDPD shows an intense absorption between 300 and 600 nm with a deeper highest occupied molecular orbital of -5.44 eV. Noticeably, PBDPD displays good complementary absorption and well-matched energy levels with various NFAs. The binary NFA OSCs are fabricated by using PBDPD without any additive or postannealing treatment, providing a maximum power conversion efficiency (PCE) of 11.24% with an impressive open-circuit voltage (V-oc) of 1.004 V and a low energy loss (E-loss) of 0.496 eV. These results suggest that PBDPD could be a useful candidate for tandem NFA OSCs. Therefore, the tandem NFA OSCs are fabricated using PBDPD with the aim of further maximizing the V-oc of the NFA OSCs. The respective tandem NFA OSCs provide an impressive PCE of 15.71% with a greatly improved V-oc of 1.73 V. This study suggests that the PD-based polymers are efficient candidates for NFA OSCs, and it opens a new platform for researchers planning to develop efficient wide band-gap polymers for NFA OSCs.