Jiang Xiu, Wang Jiacheng, Yang Yang, 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.
Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871, China.
ACS Omega. 2018 Oct 23;3(10):13894-13901. doi: 10.1021/acsomega.8b02053. eCollection 2018 Oct 31.
A new acceptor unit, fluorinated thieno[2',3':4,5]benzo[1,2-][1,2,3]triazole (fBTAZT), has been designed and synthesized to build two donor-acceptor (D-A) copolymers with the none/fluorinated benzodithiophene (BDT) unit, which have been applied as the electron-donating material with ITIC as an electron-accepting material to fabricate the nonfullerene polymer solar cells (PSCs). It is found that fluorination at the BTAZT unit and BDT unit exerts a significant influence on photophysical properties and photovoltaic performances of the PSCs. As a result, when the fluorine atom is introduced both into the BTAZT unit and the side-chain thiophene ring of the BDT unit, the corresponding polymer PfBTAZT-fBDT exhibits deeper highest occupied molecular orbital-lowest unoccupied molecular orbital energy level and shows stronger interchain interaction with a little broad and red-shift absorption and high charge mobilities as well as good phase-separated morphologies, thus leading to higher power conversion efficiency of 6.59% in nonfullerene PSCs compared with another polymer PfBTAZT-BDT without F atom at the BDT unit, indicating that fBTAZT can be acted as a medium strong organic acceptor to build D-A polymer donor for high efficient PSCs.
一种新型受体单元，即氟化噻吩并[2',3':4,5]苯并[1,2-][1,2,3]三唑（fBTAZT），已被设计并合成出来，用于构建两种含/不含氟化苯并二噻吩（BDT）单元的给体-受体（D-A）共聚物，这些共聚物已被用作给电子材料，与ITIC作为电子受体材料一起用于制备非富勒烯聚合物太阳能电池（PSC）。研究发现，BTAZT单元和BDT单元上的氟化对PSC的光物理性质和光伏性能有显著影响。结果表明，当氟原子同时引入到BTAZT单元和BDT单元的侧链噻吩环中时，相应的聚合物PfBTAZT-fBDT表现出更深的最高占据分子轨道-最低未占据分子轨道能级，显示出更强的链间相互作用，具有稍宽且红移的吸收、高电荷迁移率以及良好的相分离形态，因此与BDT单元不含F原子的另一种聚合物PfBTAZT-BDT相比，在非富勒烯PSC中导致更高的功率转换效率，达到6.59%，这表明fBTAZT可作为一种中等强度的有机受体来构建用于高效PSC的D-A聚合物给体。
