Chen Jiehuan, Tang Ningning, Zhou Jiadong, Wang Liangxuan, Jiang Nianqiang, Zheng Nan, Liu Linlin, Xie Zengqi
Institute of Polymer Optoelectronic Materials and Devices, Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, P. R. China.
J Phys Chem Lett. 2021 Apr 8;12(13):3373-3378. doi: 10.1021/acs.jpclett.1c00674. Epub 2021 Mar 30.
Coexistence of rotationally π-π stacked columns and discrete slip-stacked dimers of perylene bisimide (PBI) chromophores is revealed by single crystal X-ray diffraction in the lamellar crystal of a head-to-tail linked PBI dyad. The rotary π-π stacked columnar moieties show H-type spectral character with relatively higher excitation energy, while the discrete slip-stacked π-π dimers have J-type spectral behavior with lower excitation energy. The lamellar crystals show relatively low photoluminescence efficiency of 12% at room temperature, while this dramatically increases to ∼90% at low temperature (80 K). Both of the rotary and slip-stacked moieties are emissive, and the nonradiative energy transfer processes between them are suppressed at low temperature, ensuring the highly efficient excimer-like long-lived fluorescence.
通过对头尾相连的苝二酰亚胺（PBI）二元化合物层状晶体进行单晶X射线衍射，揭示了苝二酰亚胺（PBI）发色团的旋转π-π堆积柱与离散滑移堆积二聚体的共存。旋转π-π堆积柱状部分显示出具有相对较高激发能的H型光谱特征，而离散滑移堆积的π-π二聚体具有较低激发能的J型光谱行为。层状晶体在室温下显示出相对较低的12%的光致发光效率，而在低温（80K）下这一效率急剧增加到约90%。旋转和滑移堆积部分均有发射，并且它们之间的非辐射能量转移过程在低温下受到抑制，确保了高效的准分子样长寿命荧光。
