发色团
单重态
材料科学
有机发光二极管
激子
激发
光化学
密度泛函理论
三重态
光电子学
分子物理学
化学
凝聚态物理
原子物理学
计算化学
物理
纳米技术
激发态
图层(电子)
量子力学
作者
Xiaopeng Wang,Aizhu Wang,Mingwen Zhao,Noa Marom
标识
DOI:10.1021/acs.jpclett.3c02835
摘要
In organic light-emitting diodes (OLEDs), only 25% of electrically generated excitons are in a singlet state, S1, and the remaining 75% are in a triplet state, T1. In thermally activated delayed fluorescence (TADF) chromophores the transition from the nonradiative T1 state to the radiative S1 state can be thermally activated, which improves the efficiency of OLEDs. Chromophores with inverted energy ordering of S1 and T1 states, S1 < T1, are superior to TADF chromophores, thanks to the absence of an energy barrier for the transition from T1 to S1. We benchmark the performance of time-dependent density functional theory using different exchange-correlation functionals and find that scaled long-range corrected double-hybrid functionals correctly predict the inverted singlet-triplet gaps of N-substituted phenalene derivatives. We then show that the inverted energy ordering of S1 and T1 is an intrinsic property of graphitic carbon nitride flakes. A design strategy of new chromophores with inverted singlet-triplet gaps is proposed. The color of emitted light can be fine-tuned through flake size and amine substitution on flake vertices.
科研通智能强力驱动
Strongly Powered by AbleSci AI