Stable Large Area Organic Solar Cells Realized by Using Random Terpolymer Donors Combining with Ternary Blend Strategy
To develop efficient non-fullerene organic solar cells (NF-OSCs), it is important to utilize the absorption of each material component for realizing broad and strong absorption. Ternary blend structure is one effective strategy by employing three different materials to achieve complementary absorption spectra. Here, we first use D-A1-D-A2-type random terpolymers to enhance the absorption of ternary blend NF-OSCs. Combined with the merits of ternary blend structure, efficient NF-OSCs containing one terpolymer donor and two different molecular acceptors were investigated in detail. The weak points of the optical absorption depended largely on the DPP/BT molar ratio. The terpolymer with 0.3/0.7 molar ratio (DPP/BT) is the best candidate for filling those weak points and generating a strong and broad absorption. The best devices exhibited a good stability with a PCE of 13.63%, which could remain 80% even after 400 hours storage. High PCE of 11.43% could be also realized even in large area device (1.0 cm-2). Our work provides a useful concept to improve the absorption ability and elevate the efficiency of NF-OSCs by integrating terpolymer donor and ternary blend structure.