Insertion of chlorine atoms onto pi-bridges of conjugated polymer enables improved photovoltaic performance
Insertion of chlorine atoms onto pi-bridges of conjugated polymer enables improved photovoltaic performance
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将氯原子插入共轭聚合物的π桥上可提高光伏性能
DOI：
10.1016/j.nanoen.2019.01.039
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发表时间：
2019
期刊：
影响因子：
17.6
通讯作者：
Sun Yanming
中科院分区：
文献类型：
--
作者：
Ye Linglong;Xie Yuanpeng;Weng Kangkang;Ryu Hwa Sook;Li Chao;Cai Yunhao;Fu Huiting;Wei Donghui;Woo Han Young;Tan Songting;Sun Yanming
π桥在决定给体-π-受体-π型共轭聚合物的光吸收、带隙和能级等方面起着至关重要的作用。在这一贡献中，通过将氯原子插入到聚合物PBT1-C的π桥上，合成了一种新的聚合物给体PBT1-C-2Cl。由于氯原子的高电负性和较大的原子半径，氯原子的引入使PBT1-C-2Cl具有比PBT1-C更低的最高占据分子轨道能级和更高的结晶度。当PbT1-C-2Cl与非富勒烯受体IT-4F混合时，获得了12.7%的高功率转换效率、0.85 V的开路电压和76.0%的填充因数，均高于基于PbT1-C：IT-4F的器件的功率转换效率(Pce=10.9%，Voc=0.79 V和Ff=70.5%)。增强的电荷解离、高效的电荷传输和减少的电荷复合是提高PBT1-C-2Cl：It-4F器件光伏性能的原因。结果表明，在π桥上插入氯原子是合成高性能给体-π-受体-π型共轭聚合物给体的合理策略。
π-Bridges play a crucially important role in determining the optical absorption, bandgap and energy levels of donor-π-acceptor-π type conjugated polymers. In this contribution, a new polymer donor named PBT1-C-2Cl is synthesized by inserting the chlorine atoms onto π-bridges of the polymer PBT1-C. The introduction of chlorine atoms enables PBT1-C-2Cl with a lower highest occupied molecular orbital energy level and enhanced crystallinity than those of PBT1-C due to the high electronegativity and big atomic radius of chloride atom. When PBT1-C-2Cl is blended with the non-fullerene acceptor IT-4F, a high power conversion efficiency (PCE) of 12.7%, an open-circuit voltage (Voc) of 0.85 V and an impressive fill factor (FF) of 76.0% are achieved, which are all higher than those of PBT1-C:IT-4F based devices (PCE = 10.9%, Voc= 0.79 V and FF = 70.5%). The enhanced charge dissociation, efficient charge transport and reduced charge recombination account for the improved photovoltaic performance of PBT1-C-2Cl: IT-4F devices. The results indicate that inserting chlorine atoms onto π-bridges is a rational strategy for the synthesis of high-performance donor-π-acceptor-π type conjugated polymer donors.