Narrowband Emissive Thermally Activated Delayed Fluorescence Materials

Advanced Optical Materials, Journal Year: 2022, Volume and Issue: 10(22)

Published: Sept. 23, 2022

Abstract Organic thermally activated delayed fluorescence (TADF) materials have attracted significant research interest in the field of organic electronics because their inherent advantage 100% exciton utilization capability light‐emitting diodes (OLEDs) without use noble metals. However, despite high internal electroluminescence quantum efficiencies approaching unity, broad emission spectra with sizable full width at half maxima (FWHM; 60–100 nm) present a critical issue that must be solved for application ultrahigh‐definition OLED displays. Recently, new paradigm TADF featuring multiple resonance (MR) effect based on heteroatom‐doped polycyclic aromatic frameworks, referred to as MR‐TADF materials, has emerged and garnered considerable owing remarkable features efficient narrowband emissions extremely small FWHMs (≤30 nm). Currently, occupy prominent position cutting‐edge from both chemical physical perspectives. This review article focuses recent progress emissive systems perspective molecular design, photophysical properties, performance OLEDs. The current status future prospects this advanced material technology are discussed comprehensively.

Language: Английский

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Ultrapure green organic light-emitting diodes based on highly distorted fused π-conjugated molecular design

Nature Photonics, Journal Year: 2023, Volume and Issue: 17(3), P. 280 - 285

Published: Jan. 9, 2023

Language: Английский

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Multiple‐Resonance‐Induced Thermally Activated Delayed Fluorescence Materials Based on Indolo[3,2,1‐jk]carbazole with an Efficient Narrowband Pure‐Green Electroluminescence

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(41)

Published: Aug. 19, 2022

Herein, we report two multiple-resonance thermally activated delayed fluorescence emitters (VTCzBN and TCz-VTCzBN) based on indolo[3,2,1-jk]carbazole unit boron-nitrogen skeletons, whose emissions peaking at 496 521 nm with full width half maximum of 34 29 nm, respectively. Meanwhile, fast rate constants reverse intersystem crossing above 106 s-1 are obtained due to small singlet-triplet energy gaps large spin-orbital coupling values. Notably, planar molecular structures along the transition dipole moment direction endow them high horizontal emitting ratios up 94 %. Consequently, corresponding organic light-emitting diodes (OLEDs) show external quantum efficiencies 31.7 % 32.2 %, Particularly, OLED TCz-VTCzBN display ultra-pure green emission Commission Internationale de l'Eclairage coordinates (0.22, 0.71), consistent standard National Television System Committee.

Language: Английский

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Organoboron-based multiple-resonance emitters: synthesis, structure–property correlations, and prospects

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(3), P. 1624 - 1692

Published: Jan. 1, 2024

This review highlights organoboron-based multiple-resonance compounds’ synthetic strategies classified as one-pot borylation, one-shot and late-stage functionalisation, explores material structure–photophysical property correlations.

Language: Английский

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A Chiral Dual‐Core Organoboron Structure Realizes Dual‐Channel Enhanced Ultrapure Blue Emission and Highly Efficient Circularly Polarized Electroluminescence

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(36)

Published: July 15, 2022

The realization of luminescent materials with narrowband and circularly polarized luminescence (CPL) is great significance for the development future optical photonic devices. Herein, through a steric-hindrance-assisted dual-core strategy, two pairs chiral multiple resonance thermally activated delayed fluorescence (MR-TADF) (R/S-DOBN R/S-DOBNT) are directly constructed by bonding organoboron MR-TADF monocores (SOBN SOBNT) carbazole/3,6-di-tert-butyl-9H-carbazole phenol derivative as donors, realizing obvious CPL emissions. Furthermore, effect in prepared R/S-DOBN R/S-DOBNT increases transition oscillator strength times more than that monocore structure, while maintaining ultrapure blue emissions peaking at 453 459 nm narrower full-width half-maximum 21 reorganization energy reduction. organic light-emitting diodes based on enantiomers exhibit emission Commission Internationale de L'Eclairage (CIE) coordinates (0.14, 0.10) (0.13, 0.12), high maximum external quantum efficiencies 23.9% 25.6%, electroluminescence dissymmetry factors (|gEL |) ≈ 10-3 .

Language: Английский

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Solution‐Processable Pure‐Red Multiple Resonance‐induced Thermally Activated Delayed Fluorescence Emitter for Organic Light‐Emitting Diode with External Quantum Efficiency over 20 %

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 62(7)

Published: Dec. 13, 2022

Abstract Developing solution‐processable red organic light‐emitting diodes (OLEDs) with high color purity and efficiency based on multiple resonance thermally activated delayed fluorescence (MR‐TADF) is a formidable challenge. Herein, by introducing auxiliary electron donor acceptor moieties into the highest occupied molecular orbital (HOMO) lowest unoccupied (LUMO) distributed positions of skeleton simultaneously, an effective strategy to obtain MR‐TADF emitters was represented. The proof‐of‐the‐concept molecule BN‐R exhibits narrowband pure‐red emission at 624 nm, luminous 94 % narrow bandwidth 46 nm. Notably, fabricated OLED state‐of‐the‐art external quantum over 20 Commission Internationale de I’Éclairage coordinates (0.663, 0.337) long operational lifetime (LT 50 ) 1088 hours initial luminance 1000 cd m −2 .

Language: Английский

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

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: April 10, 2023

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

Language: Английский

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A Highly Twisted Carbazole‐Fused DABNA Derivative as an Orange‐Red TADF Emitter for OLEDs with Nearly 40 % EQE

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(47)

Published: Sept. 28, 2022

Multiple resonance (MR) type thermally activated delayed fluorescence (TADF) material is currently a research hotspot in organic light-emitting diodes (OLEDs) due to their high color purity and exciton utilization. However, there are only handful of MR-TADF emitters with emissions beyond the blue-to-green region. The very limited emission colors for mainly caused by fact that so far molecular modifications do not offer much change colors. Here, we report new approach modifying prototypical MR core DABNA fusing carbazoles framework. carbazole-fused molecule (TCZ-F-DABNA) basically maintains MR-dominated features while red-shifting emission. Its OLED achieves an external quantum efficiency 39.2 % peak at 588 nm, which record-high OLEDs peaks 560 nm. This work provides significantly tunning emitters.

Language: Английский

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Double boron-embedded multiresonant thermally activated delayed fluorescent materials for organic light-emitting diodes

Communications Chemistry, Journal Year: 2022, Volume and Issue: 5(1)

Published: Nov. 10, 2022

The subclass of multi resonant thermally activated delayed fluorescent emitters (MR-TADF) containing boron atoms has garnered significant attention in the field organic light emitting diode (OLED) research. Among boron-based MR-TADF emitters, double boron-embedded (DB-MR-TADF) show excellent electroluminescence performances with high photoluminescence quantum yields, narrow band emission, and beneficially small singlet-triplet energy levels all full-color gamut regions. This article reviews recent progress DB-MR-TADF particular to molecular design concepts, synthetic routes, optoelectronic properties, OLED performance, giving future prospects for real-world applications.

Language: Английский

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High‐Efficiency Narrowband Multi‐Resonance Emitter Fusing Indolocarbazole Donors for BT. 2020 Red Electroluminescence and Ultralong Operation Lifetime

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(30)

Published: April 19, 2023

Polycyclic heteroaromatics with multi-resonance (MR) characteristics are attractive materials for narrowband emitters in wide-color-gamut organic light-emitting diodes. However, MR pure-red colors still rare and usually exhibit problematic spectral broadening when redshifting emission. Here, a emitter is reported by fusing indolocarbazole segments into boron/oxygen-embedded skeleton, realizing BT.2020 red electroluminescence the first time together high efficiency an ultralong lifetime. The rigid segment possesses strong electron-donating ability due to its para-positioned nitrogen-π-nitrogen backbone also enlarges π-extension of skeleton suppress structural displacement during radiation, achieving concurrently redshifted narrowed emission spectrum. An maximum at 637 nm full width half-maxima merely 32 (0.097 eV) recorded toluene. corresponding device simultaneously exhibits CIE coordinates (0.708, 0.292) precisely matching point, external quantum 34.4% low roll-off LT95 (time 95% initial luminance) >10 000 h 1000 cd m-2 . These performance superior even those state-of-the-art perovskite quantum-dot-based devices this specific color, paving way toward practical applications.

Language: Английский

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