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

Chemical Society Reviews, Год журнала: 2024, Номер 53(3), С. 1624 - 1692

Опубликована: Янв. 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.

Язык: 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, Год журнала: 2022, Номер 62(7)

Опубликована: Дек. 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 .

Язык: Английский

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

Advanced Functional Materials, Год журнала: 2023, Номер 33(50)

Опубликована: Авг. 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.

Язык: Английский

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Peripherally Heavy‐Atom‐Decorated Strategy Towards High‐Performance Pure Green Electroluminescence with External Quantum Efficiency over 40 %

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(19)

Опубликована: Март 10, 2023

Heavy-atom integration into thermally activated delayed fluorescence (TADF) molecule could significantly promote the reverse intersystem crossing (RISC) process. However, simultaneously achieving high efficiency, small roll-off, narrowband emission and good operational lifetime remains a big challenge for corresponding organic light-emitting diodes (OLEDs). Herein, we report pure green multi-resonance TADF BN-STO by introducing peripheral heavy atom selenium onto parent BN-Cz molecule. The diode device based on exhibited state-of-the-art performance with maximum external quantum efficiency (EQE) of 40.1 %, power (PE) 176.9 lm W-1 , well-suppressed roll-off gamut. This work reveals feasible strategy to reach balance between fast RISC process narrow full width at half (FWHM) MR-TADF effect.

Язык: Английский

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

Chemical Communications, Год журнала: 2023, Номер 59(25), С. 3685 - 3702

Опубликована: Янв. 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.

Язык: 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, Год журнала: 2023, Номер 62(18)

Опубликована: Март 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.

Язык: Английский

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Metal‐Perturbed Multiresonance TADF Emitter Enables High‐Efficiency and Ultralow Efficiency Roll‐Off Nonsensitized OLEDs with Pure Green Gamut

Advanced Materials, Год журнала: 2022, Номер 35(6)

Опубликована: Ноя. 22, 2022

Abstract Multiresonance (MR)‐induced thermally activated delayed fluorescence (TADF) emitters based on B‐ and N‐embedded polycyclic aromatics are desirable for ultrahigh‐definition organic light‐emitting diodes (OLEDs) due to their high photoluminescence quantum yield (PLQY) narrow bandwidth. But the reverse intersystem crossing (RISC) rates of MR‐TADF usually small, resulting in severe device efficiency roll‐off at brightness. To solve this issue, a sensitizer emitter has been required. Herein, new is developed through coordination Au with B/N‐embedded ligand. Benefitting from perturbation, RISC rate dramatically accelerated 2.3 × 10 7 s −1 , leading lifetime as short 4.3 µs. Meanwhile, PLQY 95% full width half maximum 39 nm (0.18 eV) essentially unchanged after metal coordination. Therefore, PLQY, lifetime, color purity concurrently realized single TADF emitter. Accordingly, vacuum‐deposited OLEDs exhibit high‐performance electroluminescence external (EQE) 35.8% without sensitization. The EQE maintained 32.3% 000 cd m −2 . Furthermore, solution‐processed OLED also achieves excellent performance 25.7% small roll‐off.

Язык: Английский

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

Advanced Science, Год журнала: 2023, Номер 10(28)

Опубликована: Авг. 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.

Язык: 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, Год журнала: 2023, Номер 62(19)

Опубликована: Март 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 %.

Язык: Английский

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

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(20)

Опубликована: Март 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 .

Язык: Английский

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