嘉兴大学周二军团队近报道了苯基侧链氟化对高压高性能有机太阳能电池分子四极矩的调制。相关研究成果于2025年1月22日发表于国际顶尖学术期刊《美国化学会杂志》。

光活性层中的基态电荷产生（GSCG）决定了光生载流子是否占据深阱能级，进而影响有机太阳能电池（OSCs）的器件性能。

该文中，研究人员通过在BTA3侧链上引入不同数量的F原子取代的分子策略，调节电荷四极静电相互作用以实现GSCG。结果表明，8F取代（BTA3-8F）和16F取代（BTA3-16F）导致最高占据分子轨道（HOMO）和最低未占据分子轨道的能级变化模式不同。苯基侧链的全氟化使BTA3-16F的LUMO能级与BTA3相似，从而确保了高V_OC。此外，BTA3-16F具有较大的电荷四极矩，沿π-π堆叠方向促进相邻分子之间的强静电相互作用，从而在光活性成分中诱导GSCG。

这种高效的GSCG直接对光生激子解离、复合和长时间传输的后续动力学以及更大空间尺度上的非辐射复合产生了重大影响。得益于有利的GSCG和合适的能级安排，PTQ10/BTA3-16F实现了1.302 V的V_OC和11.14%的PCE，创下了V_OC大于1.3 V的OSCs性能世界纪录。此外，BTA3-16F是提高三元OSCs性能的有效客体分子，基于PM6/L8-BO/BTA3-16F的三元器件实现了19.82%的最高PCE。该结果强调了光活性组分之间的GSCG在OSCs性能中的重要作用，并证明了分子四极矩的调制是设计高效受体的有效手段。

附：英文原文

Title: Modulation of Molecular Quadrupole Moments by Phenyl Side-Chain Fluorination for High-Voltage and High-Performance Organic Solar Cells

Author: Tingting Dai, Yuhan Meng, Zongtao Wang, Jiahao Lu, Zhi Zheng, Mengzhen Du, Qing Guo, Erjun Zhou

Issue&Volume: January 22, 2025

Abstract: The ground-state charge generation (GSCG) in photoactive layers determines whether the photogenerated carriers occupy the deep trap energy levels, which, in turn, affects the device performance of organic solar cells (OSCs). In this work, charge-quadrupole electrostatic interactions are modulated to achieve GSCG through a molecular strategy of introducing different numbers of F atom substitutions on the BTA3 side chain. The results show that 8F substitution (BTA3–8F) and 16F substitution (BTA3–16F) lead to different patterns of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy level changes. The perfluorination of the phenyl side chain endows BTA3–16F with a LUMO energy level similar to that of BTA3, ensuring a high VOC. Besides, BTA3–16F features a large charge-quadrupole moment, promoting strong electrostatic interactions between neighboring molecules along the π–π stacking direction, which then induces the GSCG in photoactive components. This efficient GSCG directly makes a significant impact on the subsequent kinetics of photogenerated exciton dissociation, recombination, and transport over longer time periods, as well as on nonradiative recombination over larger spatial scales. Benefiting from the favorable GSCG and suitable energy level arrangement, PTQ10/BTA3–16F achieves a VOC of 1.302 V and a PCE of 11.14%, setting the world record for OSCs performance with a VOC greater than 1.3 V. In addition, BTA3–16F is an effective guest molecule to improve the performance of ternary OSCs, and PM6/L8-BO/BTA3–16F-based ternary device achieves the highest PCE of 19.82%. This result emphasizes the important role of GSCG between photoactive components in OSC performance and demonstrates that modulation of molecular quadrupole moments is an effective means of designing efficient acceptors.

DOI: 10.1021/jacs.4c17140

Source: https://pubs.acs.org/doi/abs/10.1021/jacs.4c17140