Benzobisoxazole Cruciforms: A Cross‐conjugated Platform for Designing Tunable Donor/Acceptor Materials
Benzobisoxazole Cruciforms: A Cross‐conjugated Platform for Designing Tunable Donor/Acceptor Materials
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DOI：
10.1002/ajoc.202000502
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发表时间：
2020-09
影响因子：
2.7
通讯作者：
Alfred A. Burney‐Allen;Jessica Shaw;David C. Wheeler;Lily Diodati;Volodimyr Duzhko;A. Tomlinson;M. Jeffries‐EL
中科院分区：
文献类型：
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作者：
Alfred A. Burney‐Allen;Jessica Shaw;David C. Wheeler;Lily Diodati;Volodimyr Duzhko;A. Tomlinson;M. Jeffries‐EL
从一个普通的合成子出发，合成了四个基于苯并[1，2-d：4，5-d‘]双恶唑(BBO)的交叉共轭分子。理论研究表明，这些十字形具有高度分离的HOMO和LUMO水平，使得能够通过沿2，6轴的替换来半自主地调节LUMO水平。实验数据证实，随着2，6轴电子密度的增加，这些体系内的HOMO能级变化了0.3 eV，而LUMO能级变化超过1.6 eV。在LUMO稳定的同时，沿2，6-轴引入了相对缺乏电子的部分，导致了吸收谱线的红移。由于4，8-和2，6-轴之间分子内电荷转移状态的改善，这些取代基还延长了光致发光寿命。在S有机太阳能电池中，BBO十字作为施主材料被评价为施主材料，但由于能级失配和较差的薄膜形貌导致性能较差。这些结果表明，苯并双恶唑十字型化合物是开发用于有机半导体的可调谐材料的一个很有前途的平台，但需要在光学、电学和成膜性能方面进行改进，以使其能够用于高效的有机半导体。
Four cross‐conjugated molecules based on the benzo[1,2‐d:4,5‐d’]bisoxazole (BBO) moiety have been synthesized from a common synthon. Theoretical studies indicated that these cruciforms had highly segregated HOMO and LUMO levels enabling semi‐autonomous tuning of the LUMO level from the HOMO through substitution along the 2,6‐axis. The experimental data confirms that the HOMO levels within these systems varied by 0.3 eV, whereas the LUMO levels varied by over 1.6 eV when the electron‐density along the 2,6‐axis was increased. The introduction of relatively electron‐deficient moieties along the 2,6‐axis resulted in a bathochromic shift in the absorption profiles concurrent with the stabilization of the LUMO. These substituents also prolonged the photoluminescent lifetimes owing to improved intramolecular charge transfer states between the 4,8‐ and 2,6‐ axis. The BBO cruciforms were evaluated as donor materials in organic solar cells (OSC)s, but the energy‐level mismatches and poor thin film morphology led to poor performance. These results indicate that benzobisoxazole cruciforms are a promising platform for the development of tunable materials for use in organic semiconductors, but improvements in the optical, electronic and film‐forming properties are needed to enable their use in efficient OSCs.