State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, China.
International Center of Future Science, Jilin University, Changchun 130012, China.
Sci Adv. 2017 May 26;3(5):e1603171. doi: 10.1126/sciadv.1603171. eCollection 2017 May.
Thermally activated delayed fluorescence (TADF) materials are inspiring intensive research in optoelectronic applications. To date, most of the TADF materials are limited to metal-organic complexes and organic molecules with lifetimes of several microseconds/milliseconds that are sensitive to oxygen. We report a facial and general "dots-in-zeolites" strategy to in situ confine carbon dots (CDs) in zeolitic matrices during hydrothermal/solvothermal crystallization to generate high-efficient TADF materials with ultralong lifetimes. The resultant CDs@zeolite composites exhibit high quantum yields up to 52.14% and ultralong lifetimes up to 350 ms at ambient temperature and atmosphere. This intriguing TADF phenomenon is due to the fact that nanoconfined space of zeolites can efficiently stabilize the triplet states of CDs, thus enabling the reverse intersystem crossing process for TADF. Meanwhile, zeolite frameworks can also hinder oxygen quenching to present TADF behavior at air atmosphere. This design concept introduces a new perspective to develop materials with unique TADF performance and various novel delayed fluorescence-based applications.
热激活延迟荧光（TADF）材料在光电应用中激发了密集的研究。迄今为止，大多数 TADF 材料仅限于具有数微秒/毫秒寿命且对氧气敏感的金属有机配合物和有机分子。我们报告了一种简便且通用的“沸石中的点”策略，即在水热/溶剂热结晶过程中将碳点（CDs）原位限制在沸石基质中，以生成具有超长寿命的高效 TADF 材料。所得的 CDs@沸石复合材料在环境温度和大气条件下表现出高达 52.14%的高量子产率和长达 350 毫秒的超长寿命。这种有趣的 TADF 现象是由于沸石的纳米受限空间可以有效地稳定 CDs 的三重态，从而实现 TADF 的反向系间穿越过程。同时，沸石骨架还可以阻止氧气猝灭，从而在空气气氛中呈现 TADF 行为。这种设计理念为开发具有独特 TADF 性能和各种新型延迟荧光应用的材料引入了新视角。
