Over 17.6% Efficiency Organic Photovoltaic Devices with Two Compatible Polymer Donors

• Published in: Solar RRL 2021-08, Vol.5 (8), p.n/a
• Main Authors: Xu, Chunyu, Ma, Xiaoling, Zhao, Zijin, Jiang, Mengyun, Hu, Zhenghao, Gao, Jinhua, Deng, Zhengqi, Zhou, Zhengji, An, Qiaoshi, Zhang, Jian, Zhang, Fujun
• Format: Article
• Language: English
• Subjects: alloyed states; compatible polymer donors; power conversion efficiency; ternary blend organic photovoltaic devices
• ISSN: 2367-198X; 2367-198X
• DOI: 10.1002/solr.202100175

Efficient ternary blend organic photovoltaic devices (OPVs) are built based on a D18‐Cl:Y6 host system and star polymer donor PM6 as the third component. A power conversion efficiency (PCE) of 16.89% is achieved in D18‐Cl:Y6 host binary OPVs, with a short‐circuit current density (J SC) of 25.31 mA cm−2, an open‐circuit voltage (V OC) of 0.878 V, and a fill factor (FF) of 75.81%. Upon incorporating appropriate PM6 in active layers, the PCE of optimal ternary blend OPVs can be increased to 17.61%, benefiting from a J SC of 26.35 mA cm−2, a V OC of 0.871 V, and an FF of 76.82%. Polymers D18‐Cl and PM6 have good compatibility and similar highest occupied molecular orbital (HOMO) levels, which enable to form D18‐Cl:PM6 alloyed states for efficient hole transport in ternary blend active layers. Meanwhile, trap density in ternary blend active layers is decreased by incorporating PM6, which is conducive to weaken charge recombination in ternary blend active layers. The gradually varied V OC values of ternary blend OPVs can be well explained from the varied HOMO levels of D18‐Cl:PM6 alloyed states. The results indicate that two compatible polymer donors with similar HOMO levels have great potential in achieving efficient ternary blend OPVs. A power conversion efficiency of 17.61% is achieved in organic photovoltaic devices (OPVs) with D18‐Cl:PM6:Y6 as active layers. The good compatibility and similar highest occupied molecular orbital levels of D18‐Cl and PM6 enable the formation of an alloyed state for efficient hole transport. Energy ransfer from D18‐Cl to PM6 should improve the exciton utilization in ternary blend OPVs.