Han Yuyi, Song Xianzhi, Wei Shuyan, Qing Yizhao, Yuan Ting, Shi Yuxin, Li Xiaohong, Li Yunchao, Tan Zhan'ao, Fan Louzhen, Zhang Yang
Key Laboratory of Theoretical & Computational Photochemistry of Ministry of Education, College of Chemistry, Beijing Normal University, Beijing, 100875, China.
Beijing Advanced Innovation Centre for Soft Matter Science and Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Adv Mater. 2025 Jul 24:e10604. doi: 10.1002/adma.202510604.
The quest for exemplary color purity, superior efficiency, and nontoxic deep-blue electroluminescence remains paramount for developing wide-color-gamut displays. However, achieving a Commission Internationale de l'Eclairage y value below 0.05, an exceptional external quantum efficiency (EQE), and a low-efficiency droop in deep-blue emitters presents a significant challenge. Here, the study reports a deep-blue emitting carbon quantum gear rack (DB-CQG) characterized by an emission wavelength of 406 nm and a high quantum yield of 80%. DB-CQG comprises nine benzene rings and four embedded nitrogen-centered tripods and exhibits a quasi-planar configuration that leads to hybridized local and charge-transfer (HLCT) excited-state characteristics. Both experimental investigations and theoretical calculations revealed the activation of the reverse intersystem crossing channel between the high-lying triplet state and lowest excited singlet state in DB-CQG via hot-exciton mechanism. DB-CQG exhibits characteristic HLCT behavior with deep-blue emission owing to the partial overlap of holes and electrons, which is facilitated by the formation of nitrogen-centered tripods in the quasi-planar configuration. The electroluminescent light-emitting diodes (LEDs) fabricated using DB-CQG exhibit a deep-blue color with chromaticity coordinates of (0.158, 0.048), a maximum luminance of 4560 cd m, and an EQE of 10.45%, which is one of the highest reported efficiencies for solution-processable deep-blue LEDs.
对于开发广色域显示器而言，追求出色的色纯度、卓越的效率以及无毒的深蓝色电致发光仍然至关重要。然而，要使国际照明委员会（CIE）的y值低于0.05、实现出色的外量子效率（EQE）以及降低深蓝色发光体的效率滚降，是一项重大挑战。在此，该研究报告了一种发射波长为406 nm、量子产率高达80%的深蓝色发光碳量子齿轮齿条（DB-CQG）。DB-CQG由九个苯环和四个嵌入的以氮为中心的三脚架组成，呈现出准平面构型，导致了局域与电荷转移（HLCT）混合激发态特征。实验研究和理论计算均表明，DB-CQG中通过热激子机制激活了高能三重态与最低激发单重态之间的反向系间窜越通道。由于空穴和电子的部分重叠，DB-CQG呈现出具有深蓝色发射的特征HLCT行为，这在准平面构型中以氮为中心的三脚架的形成的促进下得以实现。使用DB-CQG制备的电致发光二极管（LED）呈现出深蓝色，色度坐标为(0.158, 0.048)，最大亮度为4560 cd m，EQE为10.45%，这是溶液可加工深蓝色LED报道的最高效率之一。
