CAS Key Laboratory of Nanosystem and Hierarchical Fabrication, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology , Beijing 100190, P. R. China.
University of Chinese Academy of Sciences , Beijing 100049, P. R. China.
ACS Appl Mater Interfaces. 2017 Dec 20;9(50):44070-44078. doi: 10.1021/acsami.7b12550. Epub 2017 Dec 8.
On the basis of naphthalene diimide (NDI) units connected to thiophene (T), thienothiophene (TT), or dithienothiophene (DTT) units via a thiophene π-bridge, three new copolymers-PDTNDI-T, PDTNDI-TT, and PDTNDI-DTT, respectively-were synthesized and used in the fabrication of all-polymer solar cells (all-PSCs). The relationships between the structures of the polymers and their optoelectronic properties and photovoltaic performances as electron acceptors in all-PSCs were investigated in detail. As the number of copolymerized heteroaromatic rings in the DTNDI-based polymers increased, the power conversion efficiencies of the resulting all-PSCs were found to decrease. This decreasing trend in the photovoltaic performance is opposite to the results reported previously for NDI-based polymers lacking the thiophene π-bridge and naphthodithiophene diimide-based polymers. In addition, the three polymers were found to exhibit distinct molecular orientations: a face-on orientation for PDTNDI-T and edge-on orientations for PDTNDI-TT and PDTNDI-DTT. Our results indicate that large fused aromatic rings are not necessarily advantageous in the design of NDI-based polymers containing π-conjugated bridges.
基于萘二酰亚胺（NDI）单元通过噻吩（T）、噻吩并噻吩（TT）或二噻吩并噻吩（DTT）单元连接而成，分别合成了三种新型共聚物-PDTNDI-T、PDTNDI-TT 和 PDTNDI-DTT，并将其用于制备全聚合物太阳能电池（all-PSCs）。详细研究了聚合物的结构与其光电性能以及作为全聚合物太阳能电池中电子受体的光伏性能之间的关系。随着基于 DTNDI 的聚合物中共聚杂芳环数量的增加，所得全聚合物太阳能电池的功率转换效率被发现降低。这种光伏性能的下降趋势与先前报道的缺乏噻吩π桥的 NDI 基聚合物和基于萘二噻吩二酰亚胺的聚合物的结果相反。此外，这三种聚合物被发现表现出不同的分子取向：PDTNDI-T 为面向上取向，PDTNDI-TT 和 PDTNDI-DTT 为边缘向上取向。我们的结果表明，在设计含有π共轭桥的基于 NDI 的聚合物时，大的稠合芳环不一定有利。
