High-efficiency ternary sequential solution deposition structure organic solar cells with two polymer donors

Ternary organic solar cells (OSCs) as a promising device can simultaneously improve photovoltaic parameters compared with traditional binary OSCs. However, efficient ternary OSCs with two polymer donors are rarely reported due to the highly conformational freedom and incompatibility. Herein, the influences of device processing on ternary device performance were systematically studied with wide bandgap polymer donor PBB-TSD incorporated into PM6:Y6 system. The optimized traditional ternary bulk heterojunction (BHJ) OSCs achieved a PCE of 17.40%. Interestingly, the ternary sequential solution deposition (SSD) structure OSCs can effectively avoid the enrichment of acceptors at the anode and reduce the recombination. Hence, the ternary SSD structure OSC recorded a further improved PCE of 17.71%, especially compared with BHJ structure OSC (16.30%). Meanwhile, the ternary SSD structure strategy has also been applied to PM6:BTP-eC9 system with improved PCE of 18.14%. This work not only shows the potential of guest polymer donors in complementary light absorption of shortwave length range, but also reveals a simple but effective approach for boosting efficient ternary OSCs with two polymer donors.