Department of Chemistry and Centre for Plastic Electronics, Imperial College London , London SW7 2AZ, United Kindgom.
J Am Chem Soc. 2015 Jan 28;137(3):1314-21. doi: 10.1021/ja511984q. Epub 2015 Jan 14.
The design, synthesis, and characterization of a series of diketopyrrolopyrrole-based copolymers with different chalcogenophene comonomers (thiophene, selenophene, and tellurophene) for use in field-effect transistors and organic photovoltaic devices are reported. The effect of the heteroatom substitution on the optical, electrochemical, and photovoltaic properties and charge carrier mobilities of these polymers is discussed. The results indicate that by increasing the size of the chalcogen atom (S < Se < Te), polymer band gaps are narrowed mainly due to LUMO energy level stabilization. In addition, the larger heteroatomic size also increases intermolecular heteroatom-heteroatom interactions facilitating the formation of polymer aggregates leading to enhanced field-effect mobilities of 1.6 cm(2)/(V s). Bulk heterojunction solar cells based on the chalcogenophene polymer series blended with fullerene derivatives show good photovoltaic properties, with power conversion efficiencies ranging from 7.1-8.8%. A high photoresponse in the near-infrared (NIR) region with excellent photocurrents above 20 mA cm(-2) was achieved for all polymers, making these highly efficient low band gap polymers promising candidates for use in tandem solar cells.
本文报道了一系列基于二酮吡咯并吡咯的聚合物的设计、合成和特性，这些聚合物与不同的杂环二烯单体（噻吩、硒吩和碲吩）共聚，用于场效应晶体管和有机光伏器件。讨论了杂原子取代对这些聚合物的光学、电化学和光伏性能以及电荷载流子迁移率的影响。结果表明，通过增加杂原子（S < Se < Te）的大小，聚合物的能带隙变窄，主要是由于 LUMO 能级稳定。此外，较大的杂原子尺寸还增加了分子间杂原子-杂原子相互作用，促进了聚合物聚集的形成，从而提高了场效应迁移率至 1.6 cm²/（V s）。基于该杂环二烯聚合物系列与富勒烯衍生物共混的体异质结太阳能电池表现出良好的光伏性能，功率转换效率范围为 7.1-8.8%。所有聚合物在近红外（NIR）区域都表现出高的光响应，光电流超过 20 mA cm⁻²，这使得这些高效的低带隙聚合物有望成为串联太阳能电池的候选材料。
