College of Chemistry, Sichuan University, Chengdu, 610064, PR China.
Chemistry. 2012 Sep 17;18(38):12140-51. doi: 10.1002/chem.201200730. Epub 2012 Aug 14.
A new series of 2,1,3-benzothiadiazole (BT) acceptors with different conjugated aryl-vinylene side chains have been designed and used to build efficient low-bandgap (LBG) photovoltaic copolymers. Based on benzo[1,2-b:3,4-b']dithiophene and the resulting new BT derivatives, three two-dimensional (2D)-like donor (D)-acceptor (A) conjugated copolymers have been synthesised by Stille coupling polymerisation. These copolymers were characterised by NMR spectroscopy, gel-permeation chromatography, thermogravimetric analysis and differential scanning calorimetry. UV/Vis absorption and cyclic voltammetry measurements indicated that their optical and electrochemical properties can be facilely modified by changing the structures of the conjugated aryl-vinylene side chains. The copolymer with phenyl-vinylene side chains exhibited the best light harvesting and smallest bandgap of the three copolymers. The basic electronic structures of D-A model compounds of these copolymers were also studied by DFT calculations at the B3LYP/6-31G* level of theory. Polymer solar cells (PSCs) with a typical structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) (PEDOT):poly(styrenesulfonate) (PSS)/copolymer:[6,6]-phenyl-C(61) (C(71))-butyric acid-methyl ester (PCBM)/calcium (Ca)/aluminum (Al) were fabricated and measured under the illumination of AM1.5G at 100 mW cm(-2). The results showed that the device based on the copolymer with phenyl-vinylene side chains had the highest efficiency of 2.17 % with PC(71)BM as acceptor. The results presented herein indicate that all the prepared copolymers are promising candidates for roll-to-roll manufacturing of efficient PSCs. Suitable electronic, optical and photovoltaic properties of BT-based copolymers can also be achieved by fine-tuning the structures of the aryl-vinylene side chains for photovoltaic application.
一系列新的 2,1,3-苯并噻二唑(BT)受体具有不同的共轭芳基-亚乙烯基侧链,已被设计并用于构建高效的低带隙(LBG)光伏共聚物。基于苯并[1,2-b:3,4-b']二噻吩和由此产生的新 BT 衍生物,通过 Stille 偶联聚合合成了三种二维(2D)类似供体(D)-受体(A)共轭共聚物。这些共聚物通过 NMR 光谱、凝胶渗透色谱、热重分析和差示扫描量热法进行了表征。紫外/可见吸收和循环伏安法测量表明,通过改变共轭芳基-亚乙烯基侧链的结构,可以轻松地修饰它们的光学和电化学性质。具有苯基-亚乙烯基侧链的共聚物表现出三种共聚物中最佳的光捕获和最小的带隙。这些共聚物的 D-A 模型化合物的基本电子结构也通过密度泛函理论(DFT)在 B3LYP/6-31G*水平上进行了研究。采用氧化铟锡(ITO)/聚(3,4-乙二氧基噻吩)(PEDOT):聚(苯乙烯磺酸盐)(PSS)/共聚物:[6,6]-苯基-C(61)(C(71))-丁酸甲酯(PCBM)/钙(Ca)/铝(Al)的典型结构制备了聚合物太阳能电池(PSC),并在 AM1.5G 100 mW cm(-2)光照下进行了测量。结果表明,以苯基-亚乙烯基侧链为共聚物的器件具有最高的效率为 2.17%,以 PC(71)BM 为受体。本文的结果表明,所有制备的共聚物都是高效 PSCs 卷对卷制造的有前途的候选材料。通过精细调整芳基-亚乙烯基侧链的结构,还可以实现基于 BT 的共聚物的合适的电子、光学和光伏性能,以满足光伏应用的需求。