High-Crystallinity π-Conjugated Small Molecules Based on Thienylene-Vinylene-Thienylene: Critical Role of Self-Organization in Photovoltaic, Charge-Transport, and Morphological Properties
High-Crystallinity π-Conjugated Small Molecules Based on Thienylene-Vinylene-Thienylene: Critical Role of Self-Organization in Photovoltaic, Charge-Transport, and Morphological Properties
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DOI：
10.1021/acsami.8b17056
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发表时间：
2018-12-12
影响因子：
9.5
通讯作者：
Yasuda, Takuma
中科院分区：
文献类型：
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作者：
Furukawa, Seiichi;Komiyama, Hideaki;Yasuda, Takuma
具有π-延伸骨架的窄带隙小分子是用于溶液加工本体异质结（BHJ）有机太阳能电池（OSC）的有希望的供体材料。本文设计并合成了一系列以亚噻吩基-亚乙烯基-亚噻吩基（TVT）为中心D单元，以烷基取代的若丹宁或2-（1，1-二氰基亚甲基）-若丹宁为末端A单元的受体-供体-受体（A-D-A）光伏小分子。系统地研究了它们的物理性质，包括光吸收、电子能级、空穴迁移率和形貌特征。利用溶剂蒸气退火（SVA），可以适当地调节由这些小分子供体和[6，6]-苯基C-71-丁酸甲酯（PC 71 BM）受体组成的BHJ光活性层的形貌。由于供体的结晶度增加以及在快速SVA处理后供体与PC 71 BM之间的所需相分离，所得OSC器件的光伏性能经历急剧增强。本文的研究结果表明，通过合理设计基于TVT的分子骨架，并通过适当的SVA处理优化纳米级相分离形态，可以获得高效的小分子OSCs。
Narrow-band-gap small molecules with pi-rextended backbones are promising donor materials for solution-processed bulk-heterojunction (BHJ) organic solar cells (OSCs). Herein, a series of acceptor-donor-acceptor (A-D-A) photovoltaic small molecules incorporating thienylene-vinylene-thienylene (TVT) as a central D unit and alkyl-substituted rhodanine or 2-(1,1-dicyanomethylene)-rhodanine as terminal A units are designed and synthesized. Their physical properties including photoabsorption, electronic energy levels, hole mobility, and morphological characteristics are systematically investigated. Using solvent vapor annealing (SVA), the morphologies of the BHJ photoactive layers composed of these small-molecule donors and a [6,6]-phenyl C-71-butyric acid methyl ester (PC71BM) acceptor can be properly modulated. As a result of increased crystallinity of the donors and desired phase segregation between the donors and PC71BM upon rapid SVA treatment, the photovoltaic performances of the resultant OSC devices undergo drastic enhancement. The results reported here indicate that high-efficiency small-molecule OSCs can be achieved through rational design of the TVT-based molecular framework and optimization of the nanoscale phase segregated morphology via proper SVA treatment.