侧链的简单调制使近红外吸收的非富勒烯受体实现更高的短路电流密度  

Simple Modulation of Side-chains of Near-infrared AbsorbingNon-fullerene Acceptor for Higher Short-circuit Current Density

作　　者：王家成 蔡贵龙 张亚静 王嘉宇 路新慧 占肖卫[2] 陈兴国[1] WANG Jiacheng;CAI Guilong;ZHANG Yajing;WANG Jiayu;LU Xinhui;ZHAN Xiaowei;CHEN Xingguo(Hubei Key Laboratory on Organic and Polymeric Opto-electronic Materials,College of Chemistry and Molecular Sciences,Wuhan University,Wuhan 430072,China;School of Materials Science and Engineering,Peking University,Beijing 100871,China;Department of Physics,Chinese University of Hong Kong,Hong Kong 999077,China)

机构地区：[1]湖北省有机高分子光电功能材料重点实验室,武汉大学化学与分子科学学院,武汉430072 [2]北京大学材料科学与工程学院,北京100871 [3]香港中文大学物理系,中国香港999077

出　　处：《高等学校化学学报》2023年第9期118-128,共11页Chemical Journal of Chinese Universities

基　　金：国家自然科学基金(批准号:51973163)资助.

摘　　要：为了探究相同共轭骨架中不同位点引入不同侧链对相应小分子非富勒烯受体光电性能的影响,本文通过在中心核茚并二噻吩并[3,2-b]噻吩(IDT)单元和端基(1,1-二氰基亚甲基)绕丹宁单元上同时引入正辛基柔性侧链并以噻吩稠合苯并噻二唑(BTT)单元为“π-桥”而构建了一个新的A-π-D-π-A型非富勒烯受体(JC11).与以往研究得到的两个A-π-D-π-A型非富勒烯受体(A2和JC1)相比,在中心核和端基同时引入适宜长度的正辛基侧链不仅赋予JC11更有利的分子间堆叠,而且使JC11比在中心核引入刚性更强和空间位阻更大的己基取代苯基侧链的A1表现出了更大的吸收红移和更好的结晶度;同时也比在端基仅引入短链乙基侧链的JC1表现出了更好的溶解性能,避免了其与PTB7-Th给体共混时出现过度聚集而导致相分离尺度过大.此外, JC11在给体/受体共混膜中展现了比A2和JC1更高的摩尔消光系数(高达1.14×10~5 L·mol~(-1)·cm~(-1))和更高的电子迁移率(μe=1.01×10~(-3) cm·V~(-1)·s~(-1))以及更平衡的电子/空穴迁移率(μ_e/μ_h=2.72).因此,基于PTB7-Th∶JC11的太阳能电池器件经优化后实现了10.09%的光电转换效率(PCE)和高达24.20 mA/cm~2的短路电流密度(J_(SC)),超过PTB7-Th∶A2和PTB7-Th∶JC1优化器件8.20%和8.16%的PCE以及低于20 mA/cm~2的J_(SC)值.研究结果表明,调节共轭主链侧链是一种简单且有效的调控非富勒烯小分子受体材料的吸收性能和结晶性能的分子设计策略,可大幅提高异质结有机太阳能电池的J_(SC)和PCE.A long flexible side-chain of n-octyl group has been simultaneously introduced at indacenodithieno[3,2-b]thiophene(IDT)central core and(1,1-dicyanomethylene)rhodanine end-group to build a new“A-π-D-π-A”type non-fullerene acceptor(NFA)(JC11)with thiophene-fused benzothiadiazole(BTT)unit as aπ-bridge,which has been proposed to investigate the influence of different side-chains at different sites of the same conjugated backbone on the properties.Compared with the previous reported acceptors A2 and JC1,the introduction of a suitable long alkyl side-chain of octyl groups at central core and terminal group not only endows JC11 to show more favorable intermolecular stacking,thus exhibiting more red-shifted absorption and better improved crystallinity than A1 with a more rigid and steric hexylphenyl group at central core,but also ensures its better solubility to avoid the poor phase-separation morphology in the blend film with PTB7-Th than JC1 with a short ethyl side-chain at end-group.Moreover,JC11 owns a higher molar extinction coefficient of up to 1.14×105 L∙mol-1∙cm-1 and a higher electron mobility of 1.01×10-3 cm2∙V-1∙s-1 as well as more balanced electron/hole mobilities(μe/μh=2.72)in the D/A blend film than A2 and JC1.Therefore,the optimized PTB7-Th∶JC11 based device achieves a more promising power conversion efficiency(PCE)of 10.09%with a much higher short circuit current density(JSC)value of 24.20 mA/cm2,which greatly surpass the PCE of 8.20%and 8.16%with relatively low JSC values of less than 20 mA/cm2 for the optimized devices based on PTB7-Th∶A2 and PTB7-Th∶JC1,respectively.This work indicates that the regulation of side-chains is a simple but very effective strategy to improve the absorption and crystallization properties of the NFAs,thus resulting in higher JSC and PCE for bulk heterojunction organic solar cells.

关 键 词：A-π-D-π-A结构 非富勒烯受体 侧链工程 有机太阳能电池 

分 类 号：O649.5[理学—物理化学]