Synergetic Modulation of Steric Hindrance and Excited State for Anti-Quenching and Fast Spin-Flip Multi-Resonance Thermally Activated Delayed Fluorophore.
Jia-Ming JinDenghui LiuWen-Cheng ChenChengxiang ShiGuowei ChenXiaofeng WangLongjiang XingWeidong YingShaomin JiYan-Ping HuoShi-Jian SuPublished in: Angewandte Chemie (International ed. in English) (2024)
Multi-resonance thermally activated delayed fluorescence (MR-TADF) materials hold great promise for advanced high-resolution organic light-emitting diode (OLED) displays. However, persistent challenges, such as severe aggregation-caused quenching (ACQ) and slow spin-flip, hinder their optimal performance. We propose a synergetic steric-hindrance and excited-state modulation strategy for MR-TADF emitters, which is demonstrated by two blue MR-TADF emitters, IDAD-BNCz and TIDAD-BNCz, bearing sterically demanding 8,8-diphenyl-8H-indolo[3,2,1-de]acridine (IDAD) and 3,6-di-tert-butyl-8,8-diphenyl-8H-indolo[3,2,1-de]acridine (TIDAD), respectively. These rigid and bulky IDAD/TIDAD moieties, with appropriate electron-donating capabilities, not only effectively mitigate ACQ, ensuring efficient luminescence across a broad range of dopant concentrations, but also induce high-lying charge-transfer excited states that facilitate triplet-to-singlet spin-flip without causing undesired emission redshift or spectral broadening. Consequently, implementation of a high doping level of IDAD-BNCz resulted in highly efficient narrowband electroluminescence, featuring a remarkable full-width at half-maximum of 34 nm and record-setting external quantum efficiencies of 34.3 % and 31.8 % at maximum and 100 cd m -2 , respectively. The combined steric and electronic effects arising from the steric-hindered donor introduction offer a compelling molecular design strategy to overcome critical challenges in MR-TADF emitters.
Keyphrases
- light emitting
- energy transfer
- highly efficient
- contrast enhanced
- quantum dots
- single molecule
- room temperature
- high resolution
- density functional theory
- magnetic resonance
- transition metal
- healthcare
- primary care
- computed tomography
- magnetic resonance imaging
- early onset
- molecular dynamics
- mass spectrometry
- big data
- staphylococcus aureus
- optical coherence tomography
- artificial intelligence
- ionic liquid
- water soluble