Mesityl‐Functionalized Multi‐Resonance Organoboron Delayed Fluorescent Frameworks with Wide‐Range Color Tunability for Narrowband OLEDs

Wang, Xiang; Zhang, Yuewei; Dai, Hengyi; Li, Guomeng; Liu, Meihui; Meng, Gang; Zhang, Xuan; Huang, Tianyu; Wang, Lu; Peng, Qian; Yang, Dezhi; Ma, Dongge; Zhang, Dongdong; Duan, Lian

doi:10.1002/anie.202206916

Cited by 63 publications

(34 citation statements)

References 55 publications

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“…The HF OLED based on BN2 shows strong green light with an EL peak at 540 nm (CIE x,y = 0.32, 0.64; FWHM = 41 nm) and a maximum luminance as high as 33930 cd m ‒2 . Impressive η C , η P and η ext of 158.8 cd A ‒1 , 136.8 lm W ‒1 and 37.6% are achieved, being the highest EL efficiencies for green MR-TADF materials 54 , 55 .…”

Section: Resultsmentioning

confidence: 96%

Realizing efficient blue and deep-blue delayed fluorescence materials with record-beating electroluminescence efficiencies of 43.4%

Liu

Tang

et al. 2023

Nat Commun

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As promising luminescent materials for organic light-emitting diodes (OLEDs), thermally activated delayed fluorescence materials are booming vigorously in recent years, but robust blue ones still remain challenging. Herein, we report three highly efficient blue and deep-blue delayed fluorescence materials comprised of a weak electron acceptor chromeno[3,2-c]carbazol-8(5H)-one with a rigid polycyclic structure and a weak electron donor spiro[acridine-9,9’-xanthene]. They hold distinguished merits of excellent photoluminescence quantum yields (99%), ultrahigh horizontal transition dipole ratios (93.6%), and fast radiative transition and reverse intersystem crossing, which furnish superb blue and deep-blue electroluminescence with Commission Internationale de I’Eclairage coordinates (CIEx,y) of (0.14, 0.18) and (0.14, 0.15) and record-beating external quantum efficiencies (ηexts) of 43.4% and 41.3%, respectively. Their efficiency roll-offs are successfully reduced by suppressing triplet-triplet and singlet-singlet annihilations. Moreover, high-performance deep-blue and green hyperfluorescence OLEDs are achieved by utilizing these materials as sensitizers for multi-resonance delayed fluorescence dopants, providing state-of-the-art ηexts of 32.5% (CIEx,y = 0.14, 0.10) and 37.6% (CIEx,y = 0.32, 0.64), respectively, as well as greatly advanced operational lifetimes. These splendid results can surely inspire the development of blue and deep-blue luminescent materials and devices.

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Section: Resultsmentioning

confidence: 96%

Realizing efficient blue and deep-blue delayed fluorescence materials with record-beating electroluminescence efficiencies of 43.4%

Liu

Tang

et al. 2023

Nat Commun

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“…In order to achieve high-color purity deep-blue emission, narrowband chromophores with electroluminescent (EL) emission peaks at 460 ± 5 nm are required. − At the same emission peak, the narrower FWHM manifests a smaller CIE y value (and a higher current efficiency/CIE y index) and relatively lower excited state (S 1 ) energies due to the bathochromic shift for the spectral onset. However, owing to the difficulty in managing large bandgap chromophores and maintaining efficient radiative emissions, molecular design strategies for color-saturated deep-blue and high photoluminescence quantum yield (PLQY) emitters are still rare and challenging. − …”

Section: Introductionmentioning

confidence: 99%

Toward Narrowband and Efficient Blue Fluophosphors by Locking the Stretching Vibration of Indolocarbazole Skeletons

Wang

Yan

Qi-shen

et al. 2023

ACS Appl. Mater. Interfaces

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Developing efficient and color-saturated deep-blue emitting molecules with small Commission Internationale de L’Eclairage (CIE) y values is challenging and has great potential for wide-color gamut displays. Herein, we introduce an intramolecular locking strategy to restrain molecular stretching vibrations of the emission spectral broadening. By cyclizing rigid fluorenes and connecting electron-donating groups to the indolo[3,2,1-jk]-indolo[1′,2′,3′:1,7]indolo[2,3-b]carbazole (DIDCz) framework, the in-plane swing of peripheral bonds and stretching vibrations of the indolocarbazole skeleton are restricted due to an increased steric hindrance from cyclized groups and diphenylamine auxochromophores. As a result, reorganization energies at the high-frequency region (1300–1800 cm–1) are reduced, realizing pure blue emission with a small full-width-at-half-maximum (FWHM) of 30 nm by suppressing shoulder peaks of polycyclic aromatic hydrocarbon (PAH) frameworks. The fabricated bottom-emitting organic light-emitting diode (OLED) exhibits an efficient external quantum efficiency (EQE) of 7.34% and deep-blue coordinates of (0.140, 0.105) at a high brightness of 1000 cd/m2. The FWHM of the electroluminescent spectrum is only 32 nm, which is one of the narrowest electroluminescent emissions among the reported intramolecular charge transfer fluophosphors. Our current findings provide a new molecular design strategy to conceive efficient and narrowband emitters with small reorganization energies.

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“…Recently, Duan et al reported a B,N-doped pentacene emitter, mDBIC, that emits in the deep blue (lPL = 426 nm, FWHM = 26 nm) region in 2 wt% doped mCP film and was used as the terminal emitter in a HF device that showed excellent performance at the deep blue color point (lEL = 431 nm, FWHM = 42 nm, EQEmax = 13.5%, CIEy = 0.05). 21 Pushing the emission further into the deep blue in MR-TADF compounds remains exceedingly difficult. The B,N-doped heptacene system α-3BNOH (lPL = 390 nm, ΔEST = 0.30 eV, τd = 0.45 μs, THF) 22 that we previously reported represents a rare example of a MR-TADF purple emitter as does the B,O-doped triangulene emitter, DOBNA (lPL = 398 nm, ΔEST = 0.18 eV, τd = 66 μs, 1wt% in PMMA).…”

Section: Introductionmentioning

confidence: 99%

A Deep Blue Heteroatom Doped Nonacene That Exhibits Multi-Resonant Thermally Activated Delayed Fluorescence and its Use as an Emitter in High-Performance Deep Blue Organic Light-Emitting Diodes

Suresh

Zhang

Hall

et al. 2022

Preprint

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We present a p- and n-doped nonacene compound, NOBNacene, that represents a rare example of a linearly extended ladder-type multiresonant thermally activated delayed fluorescence (MR-TADF) emitter. This compound shows efficient narrow deep blue emission (PL = 410 nm, FWHM = 38 nm, ФPL = 71%, d = 1.18 ms) in 1.5 wt% TSPO1 thin film. The organic light-emitting diode (OLED) using this compound as the emitter shows a comparable electrolumines-cence spectrum (EL = 409 nm, FWHM = 37 nm) and a maximum external quantum efficiency (EQEmax) of 8.5% at CIE coordinates of (0.173, 0.055). The EQEmax values were increased to 11.2% at 3 wt% doping of the emitter within the emissive layer of the device. At this concentra-tion, the electroluminescence spectrum broadened slightly, leading to CIE coordinates of (0.176, 0.068).

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Mesityl‐Functionalized Multi‐Resonance Organoboron Delayed Fluorescent Frameworks with Wide‐Range Color Tunability for Narrowband OLEDs

Cited by 63 publications

References 55 publications

Realizing efficient blue and deep-blue delayed fluorescence materials with record-beating electroluminescence efficiencies of 43.4%

Realizing efficient blue and deep-blue delayed fluorescence materials with record-beating electroluminescence efficiencies of 43.4%

Toward Narrowband and Efficient Blue Fluophosphors by Locking the Stretching Vibration of Indolocarbazole Skeletons

A Deep Blue Heteroatom Doped Nonacene That Exhibits Multi-Resonant Thermally Activated Delayed Fluorescence and its Use as an Emitter in High-Performance Deep Blue Organic Light-Emitting Diodes

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