School of Materials Science and Engineering, Lanzhou University of Technology , Lanzhou 730050, China.
Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University , Beijing 100875, China.
ACS Appl Mater Interfaces. 2017 Oct 4;9(39):33906-33912. doi: 10.1021/acsami.7b09915. Epub 2017 Sep 25.
Three indacenodithieno[3,2-b]thiophene (IT) cored small molecular acceptors (ITIC-SC6, ITIC-SC8, and ITIC-SC2C6) were synthesized, and the influence of side chains on their performances in solar cells was systematically probed. Our investigations have demonstrated the variation of side chains greatly affects the charge dissociation, charge mobility, and morphology of the donor:acceptor blend films. ITIC-SC2C6 with four branched side chains showed improved solubility, which can ensure the polymer donor to form favorable fibrous nanostructure during the drying of the blend film. Consequently, devices based on PBDB-ST:ITIC-SC2C6 demonstrated higher charge mobility, more effective exciton dissociation, and the optimal power conversion efficiency up to 9.16% with an FF of 0.63, a J of 15.81 mA cm, and a V of 0.92 V. These results reveal that the side chain engineering is a valid way of tuning the morphology of blend films and further improving PCE in polymer solar cells.
三种茚并二噻吩[3,2-b]噻吩（IT）为核的小分子受体（ITIC-SC6、ITIC-SC8 和 ITIC-SC2C6）被合成，并且侧链对其在太阳能电池中的性能的影响被系统地研究。我们的研究表明，侧链的变化极大地影响了给体-受体共混膜中的电荷离解、电荷迁移率和形态。具有四个支链侧链的 ITIC-SC2C6 表现出更好的溶解性，这可以确保聚合物给体在共混膜干燥过程中形成有利的纤维状纳米结构。因此，基于 PBDB-ST:ITIC-SC2C6 的器件表现出更高的电荷迁移率、更有效的激子解离，以及最佳的功率转换效率可达 9.16%，填充因子为 0.63、电流密度为 15.81 mA cm 和开路电压为 0.92 V。这些结果表明，侧链工程是一种有效的调节共混膜形态并进一步提高聚合物太阳能电池中效率的方法。
