Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, Guangdong, China.
School of Energy and Chemical Engineering, Perovtronics Research Center, Low Dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, South Korea.
ACS Appl Mater Interfaces. 2023 Jun 21;15(24):29341-29351. doi: 10.1021/acsami.3c05411. Epub 2023 Jun 9.
Polythiophenes (PTs) are promising electron donors in organic solar cells (OSCs) due to their simple structures and excellent synthetic scalability. Benefiting from the rational molecular design, the power conversion efficiency (PCE) of PT solar cells has been greatly improved. Herein, five batches of the champion PT (P5TCN-F25) with molecular weights ranging from 30 to 87 kg mol were prepared, and the effect of the molecular weight on the blend film morphology and photovoltaic performance of PT solar cells was systematically investigated. The results showed that the PCEs of the devices improved first and then maintained a high value with the increase of molecular weight, and the highest PCE of 16.7% in binary PT solar cells was obtained. Further characterizations revealed that the promotion in photovoltaic performance mainly comes from finer phase separation structures and more compact molecular packing in the blend film. The best device stabilities were also achieved by polymers with high molecular weights. Overall, this study highlights the importance of optimizing the molecular weight for PTs and offers directions to further improve the PCE of PT solar cells.
聚噻吩（PTs）因其结构简单和出色的合成可扩展性，是有机太阳能电池（OSCs）中很有前途的电子给体。受益于合理的分子设计，PT 太阳能电池的光电转换效率（PCE）得到了极大的提高。在此，我们制备了五批分子量在 30 至 87kg/mol 之间的冠军 PT（P5TCN-F25），并系统地研究了分子量对 PT 太阳能电池共混膜形貌和光伏性能的影响。结果表明，器件的 PCE 先升高后保持在较高值，随着分子量的增加而增加，在二元 PT 太阳能电池中获得了 16.7%的最高 PCE。进一步的表征表明，光伏性能的提高主要来自于共混膜中更精细的相分离结构和更紧凑的分子堆积。具有高分子量的聚合物也实现了最佳的器件稳定性。总的来说，本研究强调了优化 PTs 分子量的重要性，并为进一步提高 PT 太阳能电池的 PCE 提供了方向。
