Latvian Institute of Organic Synthesis, Aizkraukles 21, LV-1006, Riga, Latvia.
Chem Commun (Camb). 2023 Jun 1;59(45):6905-6908. doi: 10.1039/d3cc01674a.
Cationic luminophores have recently emerged as a class of efficient emitters in both the solid state and solutions. However, the underlying processes that secure the emission in these luminophores are poorly understood. Here, we employ charge transfer integral (CTI) analysis in combination with X-ray single crystal data to uncover the emission mechanism in a series of pyridinium luminophores. We demonstrate that the solid state photoluminescence quantum yield () of cationic luminophores is directly proportional to the charge transfer (CT) intensity within a network of molecules in the crystal lattice. Electrostatic intermolecular interactions between π-systems in the crystal lattice provide a disproportionately high contribution to the CT intensity and therefore are instrumental in achieving high . In addition, the strength of electrostatic interactions can be increased by a through-space (TS) electron-donation strategy. Hence, electrostatic interactions can be utilized as a tool to achieve radiative CT, which is useful in the development of efficient luminophores, sensors and nonlinear optical materials.
阳离子发光体最近在固态和溶液中都成为一类高效的发射器。然而，这些发光体中确保发光的基本过程还了解甚少。在这里，我们采用电荷转移积分（CTI）分析结合 X 射线单晶数据来揭示一系列吡啶鎓发光体的发光机制。我们证明，阳离子发光体的固态光致发光量子产率（）与晶体格子中分子网络内的电荷转移（CT）强度成正比。晶体格子中π体系之间的静电分子间相互作用对 CT 强度的贡献不成比例地高，因此对实现高有很大的帮助。此外，通过空间（TS）电子给体策略可以增加静电相互作用的强度。因此，静电相互作用可以用作实现辐射 CT 的工具，这在高效发光体、传感器和非线性光学材料的开发中非常有用。
