Key Laboratory for Organic Electronics and Information Displays, Institute of Advanced Materials (IAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, P. R. China.
College of Chemistry and Materials Science, Jinan University, 601 Huang-Pu Avenue West, Guangzhou, 510632, P. R. China.
Chemistry. 2023 Feb 16;29(10):e202202915. doi: 10.1002/chem.202202915. Epub 2023 Jan 4.
Organic donor-acceptor complexes as new organic semiconductor class have attracted wide attention, due to their potential applications in functional optoelectronics. Herein, we present two new charge transfer cocrystals of di-cyanodiazafluorene -perylene (DCPE) and di-cyanodiazaflfluorene-pyrene (DCPY) through a rational cocrystal-engineering strategy. Although they are both 1 : 1 mixed stacking cocrystals with similar chemical structures, the DCPE cocrystal possesses a non-centrosymmetric space group and narrower band gap compared to DCPY cocrystal, because of the non-covalent bonding variation. The electrostatic potential accumulated in the lateral facets leads to highly twisted DCPE nanobelts, and the small band gap causes near infrared fluorescence. Meanwhile, the DCPY crystals with centrosymmetric space groups and weaker intermolecular interactions exhibited an untwisted morphology and red emission. This study will be helpful for the design and understanding of functional cocrystal materials that can be used in flexible micro/nano-mechanics, mechanical energy, and optical devices.
有机给体-受体配合物作为新的有机半导体类材料，由于其在功能光电方面的潜在应用，引起了广泛的关注。在此，我们通过合理的共晶工程策略，展示了两种新型的苝二氰基二氮杂芴（DCPE）和苝二氰基二氮杂芴（DCPY）的电荷转移共晶。尽管它们具有相似的化学结构，都是 1：1 的混合堆积共晶，但由于非共价键的变化，DCPE 共晶具有非中心对称的空间群和更窄的能带隙，而 DCPY 共晶具有中心对称的空间群和较弱的分子间相互作用。静电势在横向面上积累导致 DCPE 纳米带高度扭曲，而小的带隙导致近红外荧光。同时，具有中心对称空间群和较弱分子间相互作用的 DCPY 晶体表现出无扭曲的形态和红色发射。这项研究将有助于设计和理解可用于柔性微/纳米力学、机械能和光学器件的功能共晶材料。
