Gayathri Rajalapati Durga, Gokulnath Thavamani, Park Ho-Yeol, Kim Jeonghyeon, Kim Hyerin, Kim Jongyoun, Kim BongSoo, Lee Youngu, Yoon Jinhwan, Jin Sung-Ho
Department of Chemistry Education, Graduate Department of Chemical Materials, Institute for Plastic Information and Energy Materials, Sustainable Utilization of Photovoltaic Energy Research Center (ERC), Pusan National University, Busan 46241, Republic of Korea.
Department of Energy Science and Engineering, DGIST, Daegu 42988, Republic of Korea.
ACS Appl Mater Interfaces. 2022 Mar 2;14(8):10616-10626. doi: 10.1021/acsami.1c22784. Epub 2022 Feb 16.
End group engineering on the side chain of π-conjugated donor polymers is explored as an effective way to develop efficient photovoltaic devices. In this work, we designed and synthesized three new π-conjugated polymers (PBDT-BZ-1, PBDT-S-BZ, and PBDT-BZ-F) with terminal aryl end groups on the side chain of chlorine-substituted benzo[1,2-:4,5']dithiophene (BDT). End group modifications showed notable changes in energy levels, dipole moments, exciton lifetimes, energy losses, and charge transport properties. Remarkably, the three new polymers paired with IT-4F (halogen-free solvent processed/toluene:DPE) displayed high power conversion efficiencies (PCEs) compared to a polymer (PBDT-Al-5) without a terminal end group (PCE of 7.32%). Interestingly, PBDT-S-BZ:IT-4F (PCE of 13.73%) showed a higher PCE than the benchmark PM7:IT-4F. The improved performance of PBDT-S-BZ well correlates with its improved charge mobility, well-interdigitated surface morphology, and high miscibility with a low Flory-Huggins interaction parameter (1.253). Thus, we successfully established a correlation between the end group engineering and bulk properties of the new polymers for realizing the high performance of halogen-free nonfullerene organic solar cells.
探索π共轭供体聚合物侧链上的端基工程作为开发高效光电器件的有效方法。在这项工作中，我们设计并合成了三种新的π共轭聚合物（PBDT-BZ-1、PBDT-S-BZ和PBDT-BZ-F），它们在氯代苯并[1,2-:4,5']二噻吩（BDT）的侧链上带有末端芳基端基。端基修饰在能级、偶极矩、激子寿命、能量损失和电荷传输性质方面显示出显著变化。值得注意的是，与没有末端端基的聚合物（PBDT-Al-5，功率转换效率为7.32%）相比，这三种新聚合物与IT-4F（无卤溶剂处理/甲苯:DPE）配对时显示出高功率转换效率（PCE）。有趣的是，PBDT-S-BZ:IT-4F（PCE为13.73%）显示出比基准PM7:IT-4F更高的PCE。PBDT-S-BZ性能的提高与其电荷迁移率的提高、良好的相互交错表面形态以及与低弗洛里-哈金斯相互作用参数（1.253）的高混溶性密切相关。因此，我们成功地建立了新聚合物的端基工程与本体性质之间的相关性，以实现无卤非富勒烯有机太阳能电池的高性能。
