Details

Autor(en) / Beteiligte

• Chen, Su
• Wang, Yidan
• Lin, Jincheng
• Tian, Rundong
• Li, Shuang
• Man, Yi
• Chen, Shuo
• Zhang, Jing
• Duan, Chunbo
• Han, Chunmiao
• Xu, Hui

Titel

Phosphine oxide balanced charge transfer hybridization in multi-resonance emitters: towards ∼40% external quantum efficiency and preserved color purity

Ist Teil von

• Chemical engineering journal (Lausanne, Switzerland : 1996), 2024-06, Vol.489, p.151517, Article 151517

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Multi-resonance (MR) emitters with balanced MR and long-range charge transfer are developed through modifying with P=O acceptors (A), in which a MR-π-A emitter named TPPO-BN integrates the record-high external quantum efficiencies up to 39.8% among nonsensitized MR devices. [Display omitted] •Long-range charge transfer of P=O renders ∼100 % reverse intersystem crossing efficiency for multi-resonance molecules.•Insulating P=O acceptor limits emission red shifts and full widths at half maximum.•P=O modification doubles radiative rate constant and decreases nonradiative rate constants by two orders of magnitude.•Triplet conversion is markedly improved and quenching is effectively suppressed.•TPPO-BN realizes the photo- and electro-luminescence quantum efficiencies of 99% and 39.8%. Introducing long-range charge transfer (LRCT) effect to optimize thermally activated delayed fluorescence (TADF) properties without reducing color purities is one of the key challenges for developing high-performance multi-resonance (MR) emitters. Herein, we construct two B,N-doped polycyclic emitters of MR-Acceptor (A) type DPPO-BN and the MR-π-A type TPPO-BN through incorporating P=O groups into BCz-BN skeleton. Compared to the parent skeleton, the insulating feature of P=O averts the color purity reduction. However, the strongest LRCT markedly enhances TADF properties of DPPO-BN, making its rate constants of prompt and delayed fluorescence, singlet radiation and reverse intersystem crossing (RISC) doubled. But, intermolecular charge transfer of DPPO-BN is simultaneously strengthened. In contrast, TPPO-BN reveals the balanced MR and LRCT and enhanced vibrational coupling, leading to ∼100% RISC efficiency and two orders of magnitude decreased nonradiative rate constants. As consequence, TPPO-BN-based devices realized the state-of-the-art external quantum efficiency up to 39.8% among nonsensitized MR diodes to present.