Abstract Two 1,3-bis(thiophen-2-yl)−5,7-bis(2-ehtylhexyl)benzo-[1,2-c:4,5-c]-dithiophene-4,8-dione (BDD) based small molecules, SM1 and SM2 are designed and synthesized by incorporating benzodithiophene (BDT) central core, BDD dual accepting units and 3-ethyl rhodamine as endcap group with various number of BDT units. We systematically investigated the synthesis, optical and electrochemical properties, and photovoltaic characteristics of these donor materials. The number of BDT units have a significant influence on Jsc due to interconnected structure and results in a broader absorption on thin film. The inverted devices employed for both small molecules exhibited power conversion efficiencies of 0.41% for SM1 and 0.82% for SM2.

中文翻译：

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有机太阳能电池小分子结构工程

摘要 两个 1,3-bis(thiophen-2-yl)−5,7-bis(2-ehtylhexyl)benzo-[1,2-c:4,5-c]-dithiophene-4,8-​​dione (BDD ) 为基础的小分子，SM1 和 SM2 是通过结合苯并二噻吩 (BDT) 中心核心、BDD 双接受单元和 3-乙基罗丹明作为具有不同数量 BDT 单元的封端基团而设计和合成的。我们系统地研究了这些供体材料的合成、光学和电化学特性以及光伏特性。由于互连结构，BDT 单元的数量对 Jsc 有显着影响，并导致在薄膜上有更广泛的吸收。两种小分子所采用的倒置器件的能量转换效率对于 SM1 分别为 0.41% 和 0.82%。