Structurally Complementary Star-Shaped Unfused Ring Electron Acceptors with Simultaneously Enhanced Device Parameters for Ternary Organic Solar Cells
Structurally Complementary Star-Shaped Unfused Ring Electron Acceptors with Simultaneously Enhanced Device Parameters for Ternary Organic Solar Cells
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DOI：
10.1002/solr.202300143
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发表时间：
2023-04-19
期刊：
影响因子：
7.9
通讯作者：
Liu, Shi-Yong
中科院分区：
文献类型：
--
作者：
Huang, Xu-Min;Chen, Na;Liu, Shi-Yong
三元策略由于其潜在的改善光捕获、级联能级和优化的二元BHJ薄膜形态而引起了体异质结有机太阳能电池（BHJ OSCs）的广泛关注。本文设计并合成了三种新型的星形不融合环电子受体（SSUFREAs），即H1-3，在苯基核或外周基团上有或没有氟取代基，通过直接C-H基化作为第三组分纳入PM6:Y6 BHJ薄膜中。结构-性能-性能依赖研究表明，H1-3与PM6和Y6的各向同性电荷转移、互补的星形结构和光吸收以及能级级联使得三元BHJ比PM6:Y6二元BHJ具有更高的功率转换效率（PCE）。其中，含无氟H1的三元BHJ，即H1:PM6:Y6，其PCE最高（16.57%），这是由于分子轨道前沿位置较高，扭转角增大，提高了开路电压，抑制了Y6的过度结晶，有利于激子解离和收集。研究结果表明，SSUFREAs具有很大的潜力作为优化BHJ OSCs的形貌和提高开路电压的第三元件。
Ternary strategy has attracted extensive attention for bulk heterojunction organic solar cells (BHJ OSCs) owing to their potentially improved light harvesting, cascaded energy levels, and optimized film morphology of binary BHJs. Herein, three novel star-shaped unfused ring electron acceptors (SSUFREAs), i.e., H1-3, with and without fluorine-substituent in phenyl core or peripheral group are designed and synthesized as third components via direct C-H arylation to incorporate into PM6:Y6 BHJ films. The structure-property-performance dependence study reveals that the isotropic charge transfer, complementary star-shape structure and light absorption, and energy-level cascades of H1-3 with PM6 and Y6 allow ternary BHJs to have higher power conversion efficiency (PCE) compared to the PM6:Y6 binary BHJ. Among them, the ternary BHJ involving fluorine-free H1, i.e., H1:PM6:Y6, possesses the highest PCE (16.57%) owing to the high-lying frontier molecular orbital and the enlarged torsion angle, which enhances open-circuit voltage, inhibits the excessive crystallization of Y6, and facilitates exciton dissociation as well as collection. The findings indicate that SSUFREAs have great potential to serve as third components to optimize morphology and improve the open-circuit voltage of BHJ OSCs.