Sterically Wrapped Multiple Resonance Fluorophors for Suppression of Concentration Quenching and Spectrum Broadening

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(2)

Published: Oct. 12, 2021

Multiple resonance (MR) emitters are promising for highly efficient organic light-emitting diodes (OLEDs) with narrowband emission; however, they still face intractable challenges concentration-caused emission quenching, exciton annihilation, and spectral broadening. In this study, sterically wrapped MR dopants a fluorescent core sandwiched by bulk substituents were developed to address the reducing intermolecular interactions. Consequently, high photo-luminance quantum yields of ≥90 % small full width at half maximums (FWHMs) ≤25 nm over wide range dopant concentrations (1-20 wt %) recorded. addition, we demonstrated that emitter can effectively suppress Dexter interaction when doped in thermally activated delayed fluorescence sensitizer, eliminating loss through triplet. Within above concentration range, optimal realizes remarkably maximum external efficiencies 36.3-37.2 %, identical FWHMs 24 nm, alleviated efficiency roll-offs OLEDs.

Language: Английский

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Highly Efficient Asymmetric Multiple Resonance Thermally Activated Delayed Fluorescence Emitter with EQE of 32.8 % and Extremely Low Efficiency Roll‐Off

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(14)

Published: Feb. 1, 2022

Multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters show great potentials for high color purity organic light-emitting diodes (OLEDs). However, the simultaneous realization of photoluminescence quantum yield (PLQY) and reverse intersystem crossing rate (kRISC ) is still a formidable challenge. Herein, novel asymmetric MR-TADF emitter (2Cz-PTZ-BN) designed that fully inherits PLQY large kRISC values properly selected parent molecules. The resonating extended π-skeleton with peripheral protection can achieve 96 % fast above 1.0×105 s-1 , boost performance corresponding pure green devices an outstanding external efficiency (EQE) up to 32.8 without utilizing any sensitizing hosts. Remarkably, device sufficiently maintains EQE exceeding 23 at luminance 1000 cd m-2 representing highest value reported materials same luminescence.

Language: Английский

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Progress in the development of the display performance of AR, VR, QLED and OLED devices in recent years

Journal of Information Display, Journal Year: 2022, Volume and Issue: 23(1), P. 1 - 17

Published: Jan. 2, 2022

The remarkable progress of virtual reality, augmented quantum dot light-emitting diode, and organic diode as next-generation displays has overcome the leadership liquid crystal display during last two years. This paper discusses key technological advancements performance these new-generation devices.

Language: Английский

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Improved Efficiency and Lifetime of Deep‐Blue Hyperfluorescent Organic Light‐Emitting Diode using Pt(II) Complex as Phosphorescent Sensitizer

Advanced Science, Journal Year: 2021, Volume and Issue: 8(16)

Published: June 16, 2021

Although the organic light-emitting diode (OLED) has been successfully commercialized, development of deep-blue OLEDs with high efficiency and long lifetime remains a challenge. Here, novel hyperfluorescent OLED that incorporates Pt(II) complex (PtON7-dtb) as phosphorescent sensitizer hydrocarbon-based multiple resonance-based fluorophore an emitter (TBPDP ν-DABNA) in device emissive layer (EML), is proposed. Such EML system can promote efficient energy transfer from triplet excited states to singlet fluorophore, thus significantly improving device. As result, using (ν-DABNA) Commission Internationale de L'Eclairage chromaticity coordinate y below 0.1 demonstrated, which attains narrow full width at half maximum ≈17 nm, fourfold increased current 48.9 cd A-1 , 19-fold improved half-lifetime 253.8 h 1000 m-2 compared conventional OLED. The findings lead better understanding performance.

Language: Английский

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Development of Pure Green Thermally Activated Delayed Fluorescence Material by Cyano Substitution

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(32)

Published: June 21, 2022

Multiple resonance (MR)-effect-induced thermally activated delayed fluorescence (TADF) materials have garnered significant attention because they can achieve both high color purity and external quantum efficiency (EQE). However, the reported green-emitting MR-TADF exhibit broader emission compared to those of blue-emitting ones suffer from severe roll-off due insufficient rate constants reverse intersystem crossing process (kRISC ). Herein, a pure green material (ν-DABNA-CN-Me) with kRISC 105 s-1 is reported. The key success introduction cyano groups into (ν-DABNA), which causes remarkable bathochromic shift without loss purity. organic light-emitting diode employing it as an emitter exhibits at 504 nm small full-width half-maximum 23 nm, corresponding Commission Internationale d'Éclairage coordinates (0.13, 0.65). device achieves maximum EQE 31.9% successfully suppresses luminance.

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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Deep‐Blue OLEDs with Rec.2020 Blue Gamut Compliance and EQE Over 22% Achieved by Conformation Engineering

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(18)

Published: March 3, 2022

To achieve high-efficiency deep-blue electroluminescence satisfying Rec.2020 standard blue gamut, two thermally activated delayed fluorescent (TADF) emitters are developed: 5-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-10,10-diphenyl-5,10-dihydrodibenzo[b,e][1,4]azasiline (TDBA-PAS) and 10-(2,12-di-tert-butyl-5,9-dioxa-13b-boranaphtho[3,2,1-de]anthracen-7-yl)-9,9-diphenyl-9,10-dihydroacridine (TDBA-DPAC). Inheriting from their parented organoboron multi-resonance core, both show very promising emissions with relatively narrow full width at half-maximum (FWHM, ≈50 nm in solution), high photoluminescence quantum yield (up to 92.3%), short emission lifetime (≤2.49 µs) fast reverse intersystem crossing (>106 s-1 ) doped films. More importantly, replacing the spiro-centered sp3 C atom (TDBA-DPAC) larger-radius Si (TDBA-PAS), enhanced conformational heterogeneities bulky-group-shielded TADF molecules observed solution, film, device. Consequently, OLEDs based on TDBA-PAS retain maximum external efficiencies ≈20% suppressed efficiency roll-off color index close gamut over a wide doping range of 10-50 wt%. This study highlights new strategy restrain spectral broadening redshifting design emitters.

Language: Английский

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Highly efficient and stable deep-blue organic light-emitting diode using phosphor-sensitized thermally activated delayed fluorescence

Science Advances, Journal Year: 2022, Volume and Issue: 8(41)

Published: Oct. 14, 2022

Phosphorescent and thermally activated delayed fluorescence (TADF) blue organic light-emitting diodes (OLEDs) have been developed to overcome the low efficiency of fluorescent OLEDs. However, device instability, originating from triplet excitons polarons, limits OLED applications. Here, we develop a phosphor-sensitized TADF emission system with emitters achieve high long operational lifetime. Peripheral carbazole moieties are introduced in conventional multi-resonance-type containing one boron atom. The exciton density emitter is reduced by facilitating reverse intersystem crossing, Förster resonant energy transfer rate phosphor sensitizer enhanced absorption coefficient emitters. exhibited an lifetime 72.9 hours Commission Internationale de L'Eclairage chromaticity coordinate y = 0.165, which was 6.6 times longer than those devices using

Language: Английский

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Multiresonant TADF materials: triggering the reverse intersystem crossing to alleviate the efficiency roll-off in OLEDs

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(25), P. 3685 - 3702

Published: Jan. 1, 2023

The hunt for narrow-band emissive pure organic molecules capable of harvesting both singlet and triplet excitons light emission has garnered enormous attention to promote the advancement light-emitting diodes (OLEDs). Over past decade, thermally activated delayed fluorescence (TADF) materials based on donor (D)/acceptor (A) combinations have been researched OLEDs in wide color gamut (RGB) regions. However, due strong intramolecular charge-transfer (CT) state, they exhibit broad with full-width-at-half maximum (FWHM) > 70 nm, which deviates from being detrimental achieving high purity future high-end display electronics such as high-definition TVs ultra-high-definition (UHDTVs). Recently, new development sub-class TADF emitters called multi-resonant (MR-TADF) boron/nitrogen atoms attracted much interest ultra-high definition OLEDs. Consequently, MR-TADF are appeal their potentiality promising candidates fabricating high-efficient numerous advantages photoluminescence quantum yield (PLQY), unprecedented purity, narrow bandwidth (FWHM ≤ 40 nm). Until now many developed ultra-gamut regions different design concepts. most MR-TADF-OLEDs showed ruthless external efficiency (EQE) roll-off characteristics at brightness. Such EQE were derived mainly low reverse intersystem crossing (kRISC) rate values. This feature article primarily focuses strategies improve kRISC some supportive including extending charge delocalization, heavy atom introduction, multi-donor/acceptor utilization, a hyperfluorescence system approach. Furthermore, outlook prospects developments skeletons described.

Language: Английский

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Phosphorescent organic light-emitting devices: Iridium based emitter materials – An overview

Coordination Chemistry Reviews, Journal Year: 2023, Volume and Issue: 483, P. 215100 - 215100

Published: March 10, 2023

Language: Английский

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