Abstract We designed and synthesized three novel small molecule donors (SM1, SM2 and SM3) that consist of thiophene as the electron-donating end group and 6,7-difluoroquinoxaline moiety as a novel electron-withdrawing core group. The organic low band gap molecules with 6,7-difluoroquinoxaline and thiophene units were synthesized using Stille coupling to generate SM1, SM2 and SM3. The absorption of SM2 and SM3 in solution was red shifted due to increased conjugation length of added thiophene units. In case of SM2 and SM3, introduction of hexyl chain in terminal thiophene units improve solubility in organic solvent. The maximum absorption peaks of SM1, SM2 and SM3 in solid thin films were at 482, 505 and 518 nm, respectively. SM3 was red shifted as compare to SM2 due to increased π-π stacking of electron donor materials.

中文翻译：

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用于OSCs的具有二氟喹喔啉单元的小分子的设计和合成

摘要 我们设计并合成了三种新型小分子供体（SM1、SM2 和 SM3），它们由作为给电子端基的噻吩和作为新型吸电子核心基团的 6,7-二氟喹喔啉部分组成。使用Stille 偶联合成具有6,7-二氟喹喔啉和噻吩单元的有机低带隙分子以生成SM1、SM2 和SM3。由于添加的噻吩单元的共轭长度增加，溶液中 SM2 和 SM3 的吸收发生红移。在 SM2 和 SM3 的情况下，在末端噻吩单元中引入己基链提高了在有机溶剂中的溶解度。SM1、SM2 和 SM3 在固体薄膜中的最大吸收峰分别位于 482、505 和 518 nm。由于电子供体材料的 π-π 堆积增加，SM3 与 SM2 相比发生红移。