轮烷结构优化聚合物太阳能电池光伏性能  

Rotaxane Structure Optimizes the Photovoltaic Performance of Polymer Solar Cells

作　　者：李东旭 徐翔 宋佳鸽 梁松挺 付予昂 路新慧 邹应萍[1] Li Dongxu;Xu Xiang;Song Jiage;Liang Songting;Fu Yuang;Lu Xinhui;Zou Yingping(College of Chemistry and Chemical Engineering,Central South University,Changsha 410083;Department of Physics,The Chinese University of Hong Kong,Hong Kong 999077)

机构地区：[1]中南大学化学化工学院,长沙410083 [2]香港中文大学物理系,中国香港999077

出　　处：《化学学报》2023年第11期1500-1507,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(No.52125306)资助。

摘　　要：聚合度高低会影响聚合物太阳能电池(PSC)活性层的共混微观结构,导致其器件性能存在较大差异,一般在聚合度较低时,PSC的能量转化效率(PCE)通常因电荷传输受到影响而明显降低.为解决这一问题,本工作将环状化合物冠醚与聚合物以非共价键的方式组成轮烷结构,合成了四种具有不同冠醚含量且聚合度较低的给体材料PM6-C1、PM6-C2、PM6-C3和PM6-C4.在保留聚合物本身优异光电性质的同时,适量轮烷结构带来的非共价相互作用使活性层形成合适的纤维状网络结构和良好的相分离尺度,增强了器件的电荷提取效率,减少了陷阱/双分子复合,从而导致高的电荷传输与收集效率.基于PM6-C2的器件最终实现了16.23%的PCE,高于基于PM6-L的器件(15.33%),表明轮烷结构有助于改善聚合物太阳能电池活性层形貌,在PSC材料研究中具有极大的潜力.The degree of polymerization often affects the blending microstructure of the active layer in polymer solar cells(PSC),resulting in a large difference in device performance.Generally,when the degree of polymerization is low,the power conversion efficiency(PCE)of PSC is usually significantly reduced due to the impact of charge transport.To address this issue,we synthesized a series of polymer donors with rotaxane structure by introducing crown ether into the polymers,and four molecules PM6-C1,PM6-C2,PM6-C3 and PM6-C4 with different contents of crown ether were obtained.The rotaxane structure is composed of cyclic compounds and polymers through non-covalent bonds,which can affect intermolecular stacking by non-covalent interaction while retaining the excellent photoelectric properties of the polymer.The crown ether was randomly inserted into the backbone of polymer in the process of Stille coupling.By limiting the reaction time,the number-average molecular weight was guaranteed to be lower than 50 kDa.The devices and blend films based on the result-ant polymers were characterized by means of external quantum efficiency(EQE),light intensity dependence,mobility,atomic force microscopy(AFM),transmission electron microscopy(TEM),grazing incidence wide-angle X-ray scattering(GI-WAXS),etc.In order to study the differences in device performance caused by the different introduction methods,the crown ether was directly added as an additive,and the open-circuit voltage(Voc)and PCE of the device were significantly reduced.However,the device performance was different when the crown ether and the polymer backbone formed a rotaxane structure.Compared with PM6-L,the active layer based on PM6-C2 and Y6 exhibited an optimal fiber-like network structure and better phase separation scale,which contributed to better charge extraction efficiency and reduced trap/bimolecular recombination.Ultimately,more excellent short-circuit current density(Jsc)and fill factor(FF)were obtained because of high charge transport and collection efficienc

关 键 词：聚合物太阳能电池 非共价键 轮烷结构 冠醚 相分离尺度 

分 类 号：TQ317[化学工程—高聚物工业] TM914.4[电气工程—电力电子与电力传动]