Liu Xiaohui, Zou Yang, Wang Hai-Qiao, Wang Lei, Fang Junfeng, Yang Chuluo
Ningbo Institute of Materials Technology and Engineering , Chinese Academy of Sciences , Ningbo 315201 , China.
Hubei Key Laboratory on Organic and Polymeric Optoelectronic Materials, Department of Chemistry , Wuhan University , Wuhan 430072 , China.
ACS Appl Mater Interfaces. 2018 Nov 7;10(44):38302-38309. doi: 10.1021/acsami.8b15028. Epub 2018 Oct 24.
Manipulating the donor/acceptor (D/A) weight ratio is a critical route to produce highly efficient polymer solar cells (PSCs). However, most of the reported device performances are strongly sensitive to the blend ratio. In this work, highly efficient all-PSCs based on PBDB-T:N2200 active layer have been achieved, presenting impressive photovoltaic performance with high tolerance to wide D/A ratios ranging from 1:1 to 9:1, thus providing a broad blend ratio processing window for future practical production. In particular, the optimal device delivers the champion power conversion efficiency (PCE) of 8.61% with an outstanding fill factor (FF) of up to 75.4%, which is one of the highest FF values for the reported binary all-PSCs. Comprehensive morphological, electrical, and mechanism analysis together pointed out that the remarkable device performance are derived from the favorable interpenetrating network morphology, efficient exciton generation/dissociation, well-balanced carrier transport, and reduced bimolecular recombination. Moreover, compared to the small molecule-based and fullerene-based PSC counterparts, the all-PSCs demonstrate an excellent resilience to the D/A ratio, maintaining over 50% of the maximum PCE at a ratio of 49:1 with an extremely low acceptor content. These results depict a bright prospect of the developed all-PSCs for promising applications as flexible and scalable optoelectronic devices.
调控供体/受体（D/A）重量比是制备高效聚合物太阳能电池（PSC）的关键途径。然而，大多数已报道的器件性能对混合比例非常敏感。在这项工作中，基于PBDB-T:N2200活性层的高效全聚合物太阳能电池得以实现，在1:1至9:1的宽D/A比例范围内具有高耐受性，展现出令人印象深刻的光伏性能，从而为未来的实际生产提供了宽广的混合比例加工窗口。特别是，最优器件实现了8.61%的最高功率转换效率（PCE）以及高达75.4%的出色填充因子（FF），这是已报道的二元全聚合物太阳能电池中最高的FF值之一。综合的形态学、电学和机理分析共同指出，卓越的器件性能源自良好的互穿网络形态、高效的激子产生/解离、平衡的载流子传输以及减少的双分子复合。此外，与基于小分子和富勒烯的PSC相比，全聚合物太阳能电池对D/A比例表现出优异的耐受性，在受体含量极低的49:1比例下仍保持超过50%的最大PCE。这些结果描绘了所开发的全聚合物太阳能电池作为柔性和可扩展光电器件在有前景的应用中的光明前景。
