Synergistic Intramolecular Non-Covalent Interactions Enable Robust Pure-Blue TADF Emitters.
basic_science · Level V
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- Record sourced from PubMed, PMID 39285807.
- Also identified by DOI 10.1002/adma.202407882.
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Abstract
Stability-issues of organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) require further advancements, especially in pure-blue range of CIE<sub>y</sub> < 0.20, existing a dilemma between color purity and device lifetime. Though improving bond-dissociation-energy (BDE) can effectively improve material intrinsic stability, strategies to simultaneously improve BDE and photophysical performances are still lacking. Herein, it is disclosed that synergistic intramolecular non-covalent interactions (Intra-NI) can achieve not only the highest C─N BDE among blue TADF materials, but enhanced molecular-rigidity, near-unity photoluminescent quantum yields and short delayed lifetime. Pure-blue TADF-OLEDs based on proof-of-concept TADF material realize high external-quantum-efficiency and record-high LT<sub>80</sub>@500 cd m<sup>-2</sup> of 109 h with CIE<sub>y</sub> = 0.16. Furthermore, deep-blue TADF-sensitized devices exhibit high LT<sub>80</sub>@500 cd m<sup>-2</sup> of 81 h with CIE<sub>y</sub> = 0.10. The findings provide new insight into the critical role of Intra-NI in OLED materials and open the way to tackling vexing stability issues for developing robust pure-blue organic emitters and other functional materials.