Fully Bridged Triphenylamine Derivatives as Color-Tunable Thermally Activated Delayed Fluorescence Emitters

Zou, Sheng‐Nan; Peng, Chen‐Chen; Shen, Yang; Qu, Yang‐Kun; Yu, You‐Jun; Chen, Xing; Jiang, Zuo‐Quan; Liao, Liang‐Sheng

doi:10.1021/acs.orglett.0c04159

Cited by 100 publications

(99 citation statements)

References 28 publications

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“…The resonance effect can be significantly enhanced without compromising the color fidelity, thus improving the performance of the corresponding pure blue TADF-OLED [18]. Furthermore, several strategies for designing MR-TADF molecules have been presented, such as boron-nitrogen (BN) type [18][19][20][21], boron-oxygen type [19,22,23], and boron-carbonyl type [21,24]. Moreover, heterodoped MR-TADF emitters with triangulene backbone of different sizes have been reported [25][26][27][28][29][30]; researchers also synthesized the graphene-like BN-MR-TADF blue molecules B2 and B3 (Figure 1c,d), which are also promising blue TADF materials with small ∆E ST (0.15-0.18 eV) and narrow FWHM (32-34 nm) [31].…”

Section: Introductionmentioning

confidence: 99%

Narrowband Deep-Blue Multi-Resonance Induced Thermally Activated Delayed Fluorescence: Insights from the Theoretical Molecular Design

Zhu

Zhang

et al. 2022

Molecules

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Multi-resonance thermal activated delayed fluorescence (MR-TADF) has been promising with large oscillator strength and narrow full width at half maxima of luminescence, overcoming the compromise of emission intensity and energy criteria of traditional charge transfer TADF frameworks. However, there are still limited theoretical investigations on the excitation mechanism and systematic molecular manipulation of MR-TADF structures. We systematically study the highly localized excitation (LE) characteristics based on typical blue boron-nitrogen (BN) MR-TADF emitters and prove the potential triangular core with theoretical approaches. A design strategy by extending the planar π-conjugate core structure is proposed to enhance the multiple resonance effects. Moreover, several substituted groups are introduced to the designed core, achieving color-tunable functions with relatively small energy split and strong oscillator strength simultaneously. This work provides a theoretical direction for molecular design strategy and a series of potential candidates for highly efficient BN MR-TADF emitters.

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Section: Introductionmentioning

confidence: 99%

Narrowband Deep-Blue Multi-Resonance Induced Thermally Activated Delayed Fluorescence: Insights from the Theoretical Molecular Design

Zhu

Zhang

et al. 2022

Molecules

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“…6 Nonetheless, documented MR-TADF examples featuring promising electroluminescence remain sparse, and tactics to improve their efficiency are of great importance. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Reverse intersystem crossing (RISC) process is a critical pathway for emitters to achieve TADF. [23][24][25][26][27] A fast rate constant of RISC (kRISC) of TADF emitter can efficient converted its T1 excitons to S1 state, promising high internal quantum efficiency (IQE), while inefficient RISC would conversely increase the concentration of triplet excitons to induce triplet-triplet annihilation (TTA) or other degradation events.…”

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confidence: 99%

Heavy-atom effect promotes multi-resonance thermally activated delayed fluorescence

Hua

Zhan

et al. 2021

Chemical Engineering Journal

147

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“…12,13 A centrally positioned N-heteroatom surrounded solely by six-membered rings leads to various planar or only slightly bent architectures, such as the carbonyl, dimethyl, O, and S bridged N-heterotriangulenes, (Figure 1a, 1-4b). [14][15][16][17] Even though the latter examples prove to be strong electron donors, their modest thermal and morphological stability and high tendency towards π-π interactions impede their practical use. Non-planar species are formed when the N-dopant is partially or entirely encircled by pentagons and heptagons.…”

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confidence: 99%

TADF/RTP OLED organic emitters based on concaved N-PAHs with tunable intrinsic D-A electronic structure

Wagner

Crocomo

Kochman³

et al. 2022

Preprint

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The introduction of pyrrolic nitrogen dopants into the central sites of polycyclic aromatic hydrocarbons (PAHs) often gives rise to characteristic bowl-shaped structures due to the simultaneous introduction of 5- and/or 7-membered cycles. Although the incorporation of these heteroatoms achieves excellent electron-donating ability, the application of this strat-egy for the design of optoelectronics is hampered by typically low photoluminescence quantum yields (PLQYs). In order to address this issue, in the present study we report the synthesis and characterization of the first curved and fully conju-gated nitrogen-doped PAHs in which an electronically diverse phenazine terminus serves as the electron-accepting moie-ty. We show that the curvature of the molecular skeleton increases the spatial separation between the HOMO and the LUMO, leading to low singlet-triplet gaps, which are essential for high reverse intersystem crossing (RISC) rates. Moreo-ver, we evaluate the utility of the concave N-doped systems as TADF/RTP emitters, which has not been explored so far in the context of non-planar N-PAHs. By varying the electron-accepting ability of the phenazine terminus, we are able to tune the PLQY of the given compounds in a range from 9% to 86% (for a dinitrile substituted derivative). As a proof of con-cept, we constructed solid-state OLED devices exhibiting yellow to orange emission. The best-performing compound, built from a 3-(trifluoromethyl)phenyl decorated phenazine acceptor, shows a maximum external EL quantum efficiency (EQE) of 12%, which is the highest EQE in an curved D-A embedded N-PAH to date

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Fully Bridged Triphenylamine Derivatives as Color-Tunable Thermally Activated Delayed Fluorescence Emitters

Cited by 100 publications

References 28 publications

Narrowband Deep-Blue Multi-Resonance Induced Thermally Activated Delayed Fluorescence: Insights from the Theoretical Molecular Design

Narrowband Deep-Blue Multi-Resonance Induced Thermally Activated Delayed Fluorescence: Insights from the Theoretical Molecular Design

Heavy-atom effect promotes multi-resonance thermally activated delayed fluorescence

TADF/RTP OLED organic emitters based on concaved N-PAHs with tunable intrinsic D-A electronic structure

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