A conjugated polymer based on 5,5′-bibenzo[c][1,2,5]thiadiazole for high-performance solar cells
作者:Haifeng Wang、Pei Cheng、Yao Liu、Jianming Chen、Xiaowei Zhan、Wenping Hu、Zhigang Shuai、Yongfang Li、Daoben Zhu
DOI:10.1039/c2jm14283j
日期:——
Based on a new n-type building block 5,5â²-bibenzo[c][1,2,5]thiadiazole (BBT), we designed and synthesized a carbazoleâBBT DâA copolymer (P1), and compared it with its carbazoleâbenzo[c][1,2,5]thiadiazole (BT) analog P2. P1 has good solubility in common organic solvents, while P2 has poor solubility. In films, P1 and P2 exhibit absorption maxima at 565 and 614 nm, respectively. The HOMO level of P1 is â5.51 eV, 0.18 eV lower than that of P2, while the LUMO level of P1 is â3.56 eV, slightly lower than that of P2. The low-lying energy levels and blue-shifted absorption of P1 are attributed to the stronger electron-withdrawing ability of BBT and the twisted main chain of P1. The field-effect hole mobility of P1 is 2 Ã 10â3 cm2 Vâ1 sâ1. Polymer solar cells based on P1:PC71BM (1â:â3, w/w) exhibit a power conversion efficiency up to 3.7% with a high open circuit voltage of 0.98 V under an AM 1.5 simulated solar light at 100 mW cmâ2.
基于新型n型构建单元5,5'-联苯并[c][1,2,5]噻二唑(BBT),我们设计并合成了一种咔唑-BBT给体-受体共聚物(P1),并将其与其咔唑-苯并[c][1,2,5]噻二唑(BT)类似物P2进行了比较。P1在常见有机溶剂中具有良好的溶解性,而P2溶解性较差。在薄膜中,P1和P2的吸收峰分别位于565和614 nm。P1的HOMO能级为-5.51 eV,比P2低0.18 eV,而P1的LUMO能级为-3.56 eV,略低于P2。P1较低的能级和蓝移的吸收归因于BBT较强的吸电子能力和P1扭曲的主链。P1的场效应空穴迁移率为2×10⁻³ cm²V⁻¹s⁻¹。基于P1:PC71BM(1:3,重量比)的聚合物太阳能电池在AM 1.5模拟太阳光100 mW cm⁻²下表现出高达3.7%的能量转换效率,开路电压达0.98 V。