Teng Qian, Tan Qinghua, Hou Mengyue, Yuan Fanglong
Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
Angew Chem Int Ed Engl. 2025 Aug 4;64(32):e202508650. doi: 10.1002/anie.202508650. Epub 2025 Jun 16.
Carbon quantum dots (CQDs) are gaining increasing attention as eco-friendly alternatives to conventional heavy-metal-based QDs for full-color displays and solid-state lighting. However, the performance of CQD-based light-emitting diodes (CQD-LEDs) remains significantly lower than their heavy-metal counterparts, primarily due to the substantial energy loss from triplet excitons during electrical excitation and the reduced quantum yield (QY) in solid films. Here, we present the demonstration of bright and efficient electroluminescent LEDs based on a thermally activated sensitized fluorescence (TSF) mechanism, employing a new class of solid-state emissive (SSE) CQDs that exhibit efficient orange emission in the solid state and bright green emission when doped into host materials, with a QY exceeding 80%. By employing thermally activated delayed fluorescence (TADF) materials as both hosts and sensitizers, along with highly efficient CQDs as dopants, we significantly enhance exciton utilization through effective Förster energy transfer from sensitizers to CQDs. This strategy results in bright, efficient green CQD-LEDs, achieving a maximum luminance of approximately 16,000 cd m and a record-high current efficiency of 31 cd A. This work provides a straightforward and universal strategy for creating efficient SSE CQD-LEDs using the TSF strategy.
碳量子点（CQDs）作为传统重金属基量子点的环保替代品，在全彩显示和固态照明领域正受到越来越多的关注。然而，基于CQD的发光二极管（CQD-LEDs）的性能仍远低于基于重金属的发光二极管，这主要是由于电激发过程中三重态激子的大量能量损失以及固态薄膜中量子产率（QY）的降低。在此，我们展示了基于热激活敏化荧光（TSF）机制的明亮且高效的电致发光LED，采用了一类新型的固态发光（SSE）CQDs，其在固态中表现出高效的橙色发射，当掺杂到主体材料中时表现出明亮的绿色发射，量子产率超过80%。通过将热激活延迟荧光（TADF）材料用作主体和敏化剂，以及将高效的CQDs用作掺杂剂，我们通过从敏化剂到CQDs的有效Förster能量转移显著提高了激子利用率。这种策略产生了明亮、高效的绿色CQD-LED，实现了约16,000 cd m的最大亮度和31 cd A的创纪录高电流效率。这项工作为使用TSF策略制造高效的SSE CQD-LED提供了一种直接且通用的策略。
