An Effective Approach toward Yellow‐to‐Orange Multi‐Resonance TADF Emitters by Integrating Strong Electron Donor into B/N‐Based Polycyclic Architecture: High Performance OLEDs with Nearly 40% EQE

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(23)

Published: March 19, 2023

Abstract B/N‐based multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters and the corresponding narrow band emissive organic light‐emitting diodes (OLEDs) exhibit great potential for next‐generation high‐resolution displays. Nonetheless, designing MR‐TADF with emission wavelength over 550 nm remains challenging. Herein, an effective approach toward yellow‐to‐orange by integrating a strong electron‐donating indolophenazine building block into B/N‐doped polycyclic aromatic hydrocarbons is proposed. The investigation of photophysical properties reveals that difference between donor segments MR framework has dramatic influence on luminescent features, including full‐width at half‐maximum (FWHM). These TADF display excellent characteristics such as near‐unity photoluminescence quantum yields almost 100% horizontal dipole ratio. As result, yellow orange OLEDs employing these achieve state‐of‐the‐art device performances ultrahigh external efficiency up to nearly 40%, power 163 lm W −1 , luminance close 120 000 cd m −2 which set record among based peaks nm. More impressively, fabricated presents outstanding operational stability LT 99 110 h initial brightness 3000 .

Language: Английский

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Constructing Highly Efficient Circularly Polarized Multiple‐Resonance Thermally Activated Delayed Fluorescence Materials with Intrinsically Helical Chirality

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(42)

Published: July 18, 2023

Abstract Advanced circularly polarized multiple‐resonance thermally activated delayed fluorescence (CP‐MR‐TADF) materials synergize the advantages of luminescence (CPL), narrowband emission, and TADF characteristic, which can be fabricated into highly efficient organic light‐emitting diodes (CP‐OLEDs) with high color purity, directly facing urgent market strategic demand ultrahigh‐definition 3D displays. In this work, based on an edge‐topology molecular‐engineering (ETME) strategy, a pair high‐performance CP‐MR‐TADF enantiomers, ( P M )‐BN‐Py, is developed, merges intrinsically helical chirality MR framework. The optimized CP‐OLEDs )‐BN‐Py emitters newly developed ambipolar transport host PhCbBCz exhibit pure green emission sharp peaks 532 nm, full‐width at half‐maximum (FWHM) 37 Commission Internationale de L'Eclairage (CIE) coordinates (0.29, 0.68). Importantly, they achieve remarkable maximum external quantum efficiencies (EQEs) 30.6% 29.2%, clear electroluminescence (CPEL) signals dissymmetry factors g EL s) −4.37 × 10 −4 +4.35 for respectively.

Language: Английский

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Efficient Narrowband Circularly Polarized Light Emitters Based on 1,4‐B,N‐embedded Rigid Donor–Acceptor Helicenes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(16)

Published: Feb. 17, 2023

Narrow-band emission is essential for applicable circularly polarized luminescence (CPL) active materials in ultrahigh-definition CP-OLEDs. One of the most promising classes CPL molecules, helicenes, however, typically exhibit broad with a large Stokes shift. We present, herein, design strategy capitalizing on intramolecular donor-acceptor interactions between nitrogen and boron atoms to address this issue. 1,4-B,N-embedded configurationally stable single- double helicenes were synthesized straightforwardly. Both show unprecedentedly narrow fluorescence bands (full width at half maximum 17-28 nm, 0.07-0.13 eV) along high quantum yields (72-85 %). Quantum chemical calculations revealed that relative localization natural transition orbitals, mainly rigid core molecule, small values root-mean-square displacements S0 S1 state geometries, contribute narrower emission.

Language: Английский

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Judicious Heteroatom Doping Produces High‐Performance Deep‐Blue/Near‐UV Multiresonant Thermally Activated Delayed Fluorescence OLEDs

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(33)

Published: May 4, 2023

Two multiresonant thermally activated delayed fluorescence (MR-TADF) emitters are presented and it is shown how further borylation of a deep-blue MR-TADF emitter, DIDOBNA-N, both blueshifts narrows the emission producing new near-UV MesB-DIDOBNA-N, shown. DIDOBNA-N emits bright blue light (ΦPL = 444 nm, FWHM 64 ΦPL 81%, τd 23 ms, 1.5 wt% in TSPO1). The organic light-emitting diode (OLED) based on this twisted compound shows very high maximum external quantum efficiency (EQEmax ) 15.3% for device with CIEy 0.073. fused planar MesB-DIDOBNA-N efficient narrowband (λPL 402 19 74.7%, 133 best OLED doped co-host, highest reported at 16.2%. With coordinate 0.049, also bluest EL to date.

Language: Английский

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Deep‐Blue Narrowband Hetero[6]helicenes Showing Circularly Polarized Thermally Activated Delayed Fluorescence Toward High‐Performance OLEDs

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(1)

Published: Nov. 14, 2023

Abstract Helicenes exhibit substantial potential as circularly polarized luminescence (CPL) active molecules. However, their application in organic light‐emitting diodes (CP‐OLEDs) is typically hindered by the challenge of integrating both high color purity and efficient triplet‐harvesting capability, particularly blue spectral region. Herein, a series hetero[6]helicene‐based emitters that strategically engineered through helical extension deep‐blue double‐boron‐based multiple resonance thermally activated delayed fluorescence (MR‐TADF) motif, introduced. Importantly, does not cause apparent structural deformation or perturb frontier molecular orbitals; thus, preserving emission MR‐TADF characteristics parent molecule. This approach also leads to reduced reorganization energy, resulting with narrower linewidth higher photoluminescence quantum yield. Further, motif enhances racemization barrier improved CPL performance dissymmetry factor values up 1.5 × 10 −3 . Exploiting these merits, devices incorporating chiral dopants demonstrate within Broadcast Service Television 2020 color‐gamut range, record external efficiencies (EQEs) 29.3%, have distinctive electroluminescence (CPEL) signals. Overall, authors’ findings underscore promising strategy for designing narrowband chiroptical materials advancing high‐definition displays.

Language: Английский

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B‐N Covalent Bond Embedded Double Hetero‐[n]helicenes for Pure Red Narrowband Circularly Polarized Electroluminescence with High Efficiency and Stability

Advanced Materials, Journal Year: 2023, Volume and Issue: 36(5)

Published: Sept. 12, 2023

Chiral B/N embedded multi-resonance (MR) emitters open a new paradigm of circularly polarized (CP) organic light-emitting diodes (OLEDs) owing to their unique narrowband spectra. However, pure-red CP-MR and devices remain exclusive in literature. Herein, by introducing B-N covalent bond lower the electron-withdrawing ability para-positioned B-π-B motif, first pair double hetero-[n]helicenes (n = 6 7) emitter peaking 617 nm with small full-width at half-maximum 38 high photoluminescence quantum yield ≈100% toluene is developed. The intense mirror-image CP light produced enantiomers characterized dissymmetry factors (g

Language: Английский

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Precise Regulation of Emission Maxima and Construction of Highly Efficient Electroluminescent Materials with High Color Purity

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(19)

Published: March 11, 2023

Advanced multiple resonance induced thermally activated delayed fluorescence (MR-TADF) emitters have emerged as a privileged motif for applications in organic light-emitting diodes (OLEDs), because they furnish highly tunable TADF characteristics and high color purity emission. Herein, based on the unique nitrogen-atom embedding molecular engineering (NEME) strategy, series of compounds BN-TP-Nx (x=1, 2, 3, 4) been customized. The anchored at different position triphenylene hexagonal lattice entails varying degrees perturbation to electronic structure. newly-constructed demonstrated precise regulation emission maxima MR-TADF meet actual industrial demand, further enormously enriched reservoir. BN-TP-N3-based OLED exhibits ultrapure green emission, with peak 524 nm, full-width half-maximum (FWHM) 33 Commission Internationale de L'Eclairage (CIE) coordinates (0.23, 0.71), maximum external quantum efficiency (EQE) 37.3 %.

Language: Английский

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A Simple Molecular Design Strategy for Pure‐Red Multiple Resonance Emitters

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(20)

Published: March 15, 2023

Though the flourishment of materials with multiple resonance (MR) in blue to green regions, red-emissive MR emitters are still rare literatures, which definitely should be resolved for further applications. Herein, we report a simple molecular design strategy construction pure-red by conjugate charge transfer, could greatly enhance π-conjugation degree and charge-transfer property target molecule while maintaining basic feature MR, leading significant redshift more than 128 nm compared selected parent core. The proof-of-concept emitter PPZ-BN exhibited emission dominant peak at 613 small full-width-at-half-maximum 0.16 eV (48 nm). optimized organic light-emitting diode showed high external quantum efficiency 26.9 %, roll-off, an excellent operation stability (LT99) 43 hours initial luminance 10 000 cd m-2 .

Language: Английский

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Triptycene‐Fused Sterically Shielded Multi‐Resonance TADF Emitter Enables High‐Efficiency Deep Blue OLEDs with Reduced Dexter Energy Transfer

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(32)

Published: June 16, 2023

Designing multi-resonance (MR) emitters that can simultaneously achieve narrowband emission and suppressed intermolecular interactions is challenging for realizing high color purity stable blue organic light-emitting diodes (OLEDs). Herein, a sterically shielded yet extremely rigid emitter based on triptycene-fused B,N core (Tp-DABNA) proposed to address the issue. Tp-DABNA exhibits intense deep emissions with narrow full width at half maximum (FWHM) horizontal transition dipole ratio, superior well-known bulky emitter, t-DABNA. The MR skeleton of suppresses structural relaxation in excited state, reduced contributions from medium- high-frequency vibrational modes spectral broadening. hyperfluorescence (HF) film composed sensitizer shows Dexter energy transfer compared those t-DABNA DABNA-1. Notably, TADF-OLEDs display higher external quantum efficiencies (EQEmax =24.8 %) narrower FWHMs (≤26 nm) than t-DABNA-based OLEDs =19.8 %). HF-OLEDs further demonstrate improved performance an EQEmax 28.7 % mitigated efficiency roll-offs.

Language: Английский

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Improving the stability and color purity of a BT.2020 blue multiresonance emitter by alleviating hydrogen repulsion

Science Advances, Journal Year: 2023, Volume and Issue: 9(19)

Published: May 12, 2023

Stable deep blue multiresonance emitters with small full width at half maximum (FWHM) are attractive for wide color-gamut organic light-emitting diodes (OLEDs). However, the steric repulsion from spatially close hydrogens would twist skeletons, causing spectral broadening and molecular instability issues. Here, we strategically introduce a mesitylboron locking unit into carbazole-embedded model emitter, alleviating hydrogen repulsions also strengthening para-positioned weak carbon-nitrogen bond in anionic states. An emission peaking 452 nm an FWHM of merely 14 nearly BT.2020 chromaticity coordinates obtained toluene, affording high external quantum efficiency 33.9% sensitizing device. Moreover, impressive LT97 (time to decay 97% initial luminance) 178 hours constant current density 12 mA/cm2 was achieved stable device y coordinate 0.057, 20 times longer than emitter even substantially red-shifted emission.

Language: Английский

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