15.4% Efficiency all-polymer solar cells

We report all-polymer solar cells (All-PSCs) with record-high power conversion efficiency (PCE) through tuning the molecular weights of the polymer donor (PBDB-T) to form optimal active layer morphology. By combining the polymer donors with a newly reported polymer acceptor (PJ1), an unprecedented high PCE of 15.4% and fill factor over 75% were achieved for the All-PSCs with the medium molecular weight polymer donor (PBDB-T-MW), which is the highest value for All-PSCs reported so far. Detailed morphology investigation revealed that the proper phase separation in the PBDB-T-MW:PJ1 blend should account for the superior device performance as PBDB-T-MW exhibits appropriate miscibility with the polymer acceptor PJ1. These results demonstrated that the device performance of All-PSCs could be fully comparable to that of small molecular acceptor-based PSCs. The formation of optimized morphology via precise control of molecular weights of polymer donors and acceptors is crucial to achieve this goal.

Automated summary

By tuning the molecular weights of the polymer donor, researchers achieved a record-high power conversion efficiency in all-polymer solar cells. The combination of polymer donors with a newly reported polymer acceptor resulted in unprecedented high PCE and fill factor values. Detailed morphology investigation revealed the importance of proper phase separation in achieving superior device performance in all-polymer solar cells.