A universal strategy via polymerizing non-fullerene small molecule acceptors enables efficient all-polymer solar cells with > 1 year excellent thermal stability

Authors：Li, Zhenye^*; Peng, Feng; Quan, Huilei; Qian, Xitang; Ying, Lei^*; Cao, Yong

Source：Chemical Engineering Journal, 2022, 430: 132711.

DOI：10.1016/j.cej.2021.132711

• Polymer solar cells
• Polymerizing non-fullerene small molecule acceptors
• All-polymer solar cells
• Thermal stability

Record-holding polymer solar cells (PSCs) composed of polymer donors and Y-series non-fullerene small molecule acceptors have reached the efficiency threshold for commercialization, but this type of PSCs is often difficult to work continuously and stably at high temperatures close to 100 degrees C, limiting its outdoor application. Therefore, in this work, we tried to boost the thermal stability of PSCs based on Y-series acceptors Y5-F-Br by polymerizing Y5-F-Br obtaining PFA1, and establish a precise correlation between the molecular structure and device thermal stability. Consequently, the excellent film stability based on long-chain acceptor PFA1 effectively suppressed the thermally induced phase separation of PTzBI-oF:PFA1 blend film at high temperatures, resulting in over 98% thermal stability at 100 degrees C for over 1 year in the nitrogen-filled glovebox. Furthermore, the use of long-chain acceptor for improving thermal stability was also confirmed in other two commonly used PSCs, suggesting that polymerizing non-fullerene small molecule acceptors is an effective and universal strategy to boost the thermal stability of PSCs.