Influences of Quinoid Structures on Stability and Photovoltaic Performance of Nonfullerene Acceptors
Influences of Quinoid Structures on Stability and Photovoltaic Performance of Nonfullerene Acceptors
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醌型结构对非富勒烯受体稳定性和光伏性能的影响
DOI：
10.1002/solr.202000286
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发表时间：
2020-08-09
期刊：
影响因子：
7.9
通讯作者：
Chen, Hongzheng
中科院分区：
文献类型：
--
作者：
Lv, Ruizhi;Geng, Shizhe;Chen, Hongzheng
虽然具有强醌型特征的苯并唑稠环已被成功地用于构建高性能的小分子非富勒烯受体（NFA），但迄今为止，关于这些单元如何影响NFA的稳定性及其相应的器件性能的研究很少。针对这一问题，设计并研究了四种分别以BBT、TBZ和BTAZ为核心的NFA，即SSTI、SNTI、NTI和NTTI。结果表明，基于BBT和TBZ核的SSTI和SNTI具有较强的醌型共振效应，具有更深的能级和更多的红移，但热稳定性和光稳定性比基于BTAZ核的NTI和NTTI差，特别是在溶液和/或与聚合物供体共混的薄膜中。通过对降解产物的基质辅助激光解吸电离飞行时间质谱分析，揭示了较强的醌式效应会加速C（sic）C双键的断裂。因此，具有相对较弱的醌型特征的NTI和NTTI显示出改善的光伏性质。特别地，基于NTTI的器件产生8.61%的良好效率，因为sp3杂化C原子上的侧链可以防止大聚集体的形成。这些发现为高效、高稳定性的NFA的分子设计提供了宝贵的知识
Although benzoazole-fused rings with strong quinoid character have successfully been used to construct high-performance small-molecule non-fullerene acceptors (NFAs), studies into how these units influence the stabilities of NFAs and their corresponding device performances are few to date. To address it, four new NFAs, SSTI, SNTI, NTI and NTTI, which adopt BBT, TBZ, and BTAZ as the cores, respectively, are designed and investigated. It is found that SSTI and SNTI based on BBT and TBZ cores with stronger quinoid resonance effects show features of more red-shifted absorptions and deeper energy levels, but worse thermal and light stabilities than NTI and NTTI with a BTAZ core, especially in solutions and/or films blended with polymer donors. Through matrix-assisted laser desorption ionization time of flight mass spectrometry analysis of the degradation products, it is disclosed that the C(sic)C double bond cleavage would be accelerated by stronger quinoid effects. Therefore, NTI and NTTI with relatively weaker quinoid characteristics show improved photovoltaic properties. Especially, NTTI based devices yield a good efficiency of 8.61% as the side chains on sp3-hybrid C atoms can prevent the formation of large aggregates. These findings can provide invaluable knowledge for the molecular design of NFAs with both high-efficiency and high-stability