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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Charge Transfer Excited State Promoted Multiple Resonance Delayed Fluorescence Emitter for High-Performance Narrowband Electroluminescence

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(23), P. 12550 - 12560

Published: June 5, 2023

Multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters are promising candidates for narrowband organic light-emitting diodes, but their electroluminescent performance is typically hindered by the slow reverse intersystem crossing rate (kRISC). Herein, we present an effective strategy to introduce a multichannel (RISC) pathway with large spin-orbit coupling orthogonally linking electron-donating unit MR framework. Through delicate manipulation of excited-state energy levels, additional intersegmental charge transfer triplet state could be "silently" induced without perturbing character lowest excited singlet state. The proof-of-concept emitter CzBN3 not only affords 23-fold increase kRISC compared its prototypical skeleton also realizes close-to-unity photoluminescence quantum yield, radiative constant, and very narrow emission spectrum. These merits enable high maximum external efficiency (EQEmax) up 37.1% alleviated roll-off in sensitizer-free device (EQE1000 = 30.4%), further boost (EQEmax/1000 42.3/34.1%) realized hyperfluorescent device. state-of-the-art validates superiority our molecular design strategy.

Language: Английский

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Sequential Multiple Borylation Toward an Ultrapure Green Thermally Activated Delayed Fluorescence Material

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 145(3), P. 1505 - 1511

Published: Dec. 22, 2022

Multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters have emerged as an important component of organic light-emitting diodes (OLEDs) because their narrowband emission and high exciton utilization efficiency. However, the chemical space MR-TADF remains mostly unexplored lack suitable synthetic protocols. Herein, we demonstrate a sequential multiple borylation reaction that provides new synthetically accessible space. ω-DABNA, proof-of-concept material, exhibited green TADF with full width at half-maximum 22 nm small singlet-triplet energy gap 13 meV. The OLED employing it emitter electroluminescence 512 nm, Commission International de l'Éclairage coordinates (0.13, 0.73) external quantum efficiency (EQE) 31.1%. Moreover, device showed minimum roll-off, EQE 29.4% 1000 cd m-2.

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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High‐Performance Multi‐Resonance Thermally Activated Delayed Fluorescence Emitters for Narrowband Organic Light‐Emitting Diodes

Advanced Functional Materials, Journal Year: 2023, Volume and Issue: 33(50)

Published: Aug. 7, 2023

Abstract Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) emitters have drawn considerable attention because of their remarkable optoelectronic properties high emission efficiency and narrow profile, represent an active subject cutting‐edge research in the organic electroluminescence (EL). However, slow reverse intersystem crossing (RISC) rate MR‐TADF emitter caused by large energy gap (Δ E ST ) small spin‐orbit coupling (SOC) matrix elements between singlet triplet excited states limits further development EL devices. Currently, innovative molecular design strategies been developed including heavy atom integration, π‐extended MR framework metal perturbation, so on to improve RISC process for high‐performance Here, overview is presented recent progress with fast ( > 10 −5 s −1 ), particular design, properties, device performance light‐emitting diodes (OLEDs), which intends systematize knowledge this thriving highly efficient emitters. Finally, challenges future prospects materials are discussed comprehensively.

Language: Английский

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Multiple Fusion Strategy for High‐Performance Yellow OLEDs with Full Width at Half Maximums Down to 23 nm and External Quantum Efficiencies up to 37.4%

Advanced Materials, Journal Year: 2022, Volume and Issue: 35(7)

Published: Nov. 27, 2022

The pursuit of ideal narrowband yellow multiple resonance (MR) emitters is hampered by the mutual constraints effective spectral redshift and maintaining a small full width at half maximum (FWHM) value. Here, novel fusion molecular design strategy reported to break this trade-off. Compared with selected parent core, specific MR effects in target molecules can simultaneously extend π-conjugation length, increase rigidity structure, reduce vibrational frequency. Proof-of-the-concept BN-DICz DBN-ICz show bright yellowish green emissions dilute toluene solutions peaks 533-542 nm extremely FWHMs ≤20 nm. Notably, BN-DICz-based electroluminescent device exhibits excellent efficiencies 37.4%, 136.6 cd A-1 , 119.2 lm W-1 an FWHM merely 23 nm, representing best performance for organic light-emitting diodes.

Language: Английский

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Integrating Asymmetric O−B−N Unit in Multi‐Resonance Thermally Activated Delayed Fluorescence Emitters towards High‐Performance Deep‐Blue Organic Light‐Emitting Diodes

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(18)

Published: March 3, 2023

Developing deep-blue thermally activated delayed fluorescence (TADF) emitters with both high efficiency and color purity remains a formidable challenge. Here, we proposed design strategy by integrating asymmetric oxygen-boron-nitrogen (O-B-N) multi-resonance (MR) unit into traditional N-B-N MR molecules to form rigid extended O-B-N-B-N π-skeleton. Three MR-TADF of OBN, NBN ODBN featuring O-B-N, symmetric units were synthesized through the regioselective one-shot electrophilic C-H borylation at different positions same precursor. The proof-of-concept emitter exhibited respectable emission Commission International de l'Eclairage coordinate (0.16, 0.03), photoluminescence quantum yield 93 % narrow full width half maximum 26 nm in toluene. Impressively, simple trilayer OLED employing as achieved external up 24.15 accompanied deep blue corresponding CIE y below 0.1.

Language: Английский

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One-Shot Construction of BN-Embedded Heptadecacene Framework Exhibiting Ultra-narrowband Green Thermally Activated Delayed Fluorescence

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(21), P. 11504 - 11511

Published: May 16, 2023

BN-embedded nonacene, tridecacene, and heptadecacene frameworks were constructed using one-shot quadruple, sextuple, octuple borylation reactions, respectively. The key to success is the judicious choice of borylating reagents long-chain alkyl-substituted carbazolyl groups as boron-trapping groups, which suppressed decrease in HOMO energy insolubilization associated with borylation. Based on product yields, each electrophilic C-H proceeded >99% yield, best efficiency reported so far for reactions. Owing multiple resonance effects boron nitrogen, prepared acenes exhibited ultra-narrowband green thermally activated delayed fluorescence full-width at half-maximum 12-16 nm; moreover, their kRISC values order 105 s-1. We fabricated an organic light-emitting diode by employing nonacene emitter, high external quantum (EQE) 28.7%. device also showed a minimum roll-off EQE 25.8% 1000 cd m-2.

Language: Английский

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RGB Thermally Activated Delayed Fluorescence Emitters for Organic Light‐Emitting Diodes toward Realizing the BT.2020 Standard

Advanced Science, Journal Year: 2023, Volume and Issue: 10(28)

Published: Aug. 16, 2023

Abstract With the surging demand for ultra‐high‐resolution displays, International Telecommunication Union (ITU) announce next‐generation color gamut standard, named ITU‐R Recommendation BT.2020, which not only sets a seductive but challenging milestone display technologies also urges researchers to recognize importance of coordinates. Organic light‐emitting diodes (OLEDs) are an important technology in current daily life, they face challenges approaching BT.2020 standard. Thermally activated delayed fluorescence (TADF) emitters have bright prospects OLEDs because possess 100% theoretical exciton utilization. Thus, development TADF emitting primary red (R), green and blue (B) emission is great significance. Here, comprehensive overview latest advancements that exhibit Commission Internationale de l'Éclairage (CIE) coordinates surpassing National Television System Committee (NTSC) standards presented. Rational strategies molecular designs, as well resulting photophysical properties OLED performances, discussed elucidate underlying mechanisms shifting CIE both donor‐acceptor multiple resonance (MR) typed toward Finally, realization wide‐color‐gamut standard this research area provided.

Language: Английский

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