透過超分子策略開發高效率熱激活化延遲螢光材料

Abstract

本研究以透過超分子化學策略建構供體−受體結構，進一步實現激發態複合物（exciplex）發光機制。在本研究中，我們以超分子策略建構具有圓偏振熱激活延遲螢光（CP-TADF）能力的 exciplex 發光系統。我們設計並合成了具手性的供體分子，並與三嗪基籠狀受體Trz-cage形成超分子複合物，經由核磁共振光譜（NMR）分析確認其形成。單晶 X 光繞射結構顯示，供體與Trz-cage之間具有緊密堆疊，這種堆疊模式對於手性誘導的分子間電荷轉移至關重要。經由完整的光物理性質研究，我們觀察到該複合物展現顯著的exciplex型CP-TADF放光行為，其圓偏振放光不對稱因子（|glum|）可達 10⁻2。此外，本研究亦探討引入輪烷（rotaxane）結構將供體單元鎖定於籠體中，透過空間阻礙形成穩定激發複合物，並應用於有機發光二極體中，相較於complex型的exciplex材料，rotaxane型的exciplex材料具有更高的光穩定性，可以作為一種新型態的有機發光二極體材料。

In this study, we employed a supramolecular chemistry strategy to construct a donor–acceptor system capable of generating exciplex emission. A supramolecular approach was used to develop an exciplex-based circularly polarized thermally activated delayed fluorescence (CP-TADF) system. A chiral donor molecule was rationally designed and synthesized, and was subsequently assembled with a triazine-based cage acceptor (Trz-cage) to form a supramolecular complex, as confirmed by nuclear magnetic resonance (NMR) spectroscopy. Single-crystal X-ray diffraction analysis revealed a tight packing between the donor and Trz-cage, which is essential for efficient intermolecular charge transfer induced by chirality. Comprehensive photophysical characterization demonstrated that the resulting complex exhibits pronounced exciplex-type CP-TADF emission, with a |glum| value reaching up to 10⁻2. In addition, we further explored the incorporation of a rotaxane structure to lock the donor unit within the cage. This spatial confinement enables the formation of a more stable excited-state complex through steric restriction. The new rotaxane was applied as emitter for organic light-emitting diodes (OLEDs). Compared to the non-interlocked exciplex system (complex), the rotaxane-based exciplex material exhibited enhanced photostability, highlighting its potential as a novel class of OLED-active materials.