Chiral Multi‐Resonance TADF Emitters Exhibiting Narrowband Circularly Polarized Electroluminescence with an EQE of 37.2 %

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(30)

Published: May 10, 2022

Highly efficient circularly polarized luminescence (CPL) emitters with narrowband emission remain a formidable challenge for OLEDs (CP-OLEDs). Here, promising strategy developing chiral concurrently featuring multi-resonance thermally activated delayed fluorescence (MR-TADF) and electroluminescence (CPEL) is demonstrated by the integration of molecular rigidity, central chirality MR effect. A pair green denoted as (R)-BN-MeIAc (S)-BN-MeIAc designed. Benefited rigid quasi-planar MR-framework, enantiomers not only display mirror-image CPL spectra, but also exhibit TADF properties high photoluminescence quantum yield 96 %, narrow FWHM 30 nm, horizontal dipole orientation 90 % in doped film. Consequently, enantiomer-based CP-OLEDs achieved excellent external efficiencies 37.2 very low efficiency roll-off, representing highest device all reported CP-OLEDs.

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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B,N‐Embedded Hetero[9]helicene Toward Highly Efficient Circularly Polarized Electroluminescence

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(18)

Published: Feb. 21, 2024

The intrinsic helical π-conjugated skeleton makes helicenes highly promising for circularly polarized electroluminescence (CPEL). Generally, carbon undergo low external quantum efficiency (EQE), while the incorporation of a multi-resonance thermally activated delayed fluorescence (MR-TADF) BN structure has led to an improvement. However, reported B,N-embedded all show dissymmetry factors (g

Language: Английский

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Energy‐Efficient Stable Hyperfluorescence Organic Light‐Emitting Diodes with Improved Color Purities and Ultrahigh Power Efficiencies Based on Low‐Polar Sensitizing Systems

Advanced Materials, Journal Year: 2023, Volume and Issue: 35(22)

Published: March 9, 2023

Multi-resonance (MR) molecules with thermally activated delayed fluorescence (TADF) are emerging as promising candidates for high-definition displays because of their narrow emission spectra. However, the electroluminescence (EL) efficiencies and spectra MR-TADF highly sensitive to hosts sensitizers when applied organic light-emitting diodes (OLEDs), polar environments in devices often lead significantly broadened EL In this study, a proof-of-concept TADF sensitizer (BTDMAC-XT) low polarity, high steric hindrance, concentration-quenching free feature is constructed, which acts good emitter doped non-doped OLEDs external quantum (ηext s) 26.7% 29.3%, respectively. By combining BTDMAC-XT conventional low-polarity hosts, sensitizing systems small carrier injection barrier full exciton utilization constructed molecule BN2. Hyperfluorescence (HF) employing low-polar successfully improve color quality BN2 afford an excellent ηext 34.4%, record-high power efficiency 166.3 lm W-1 long operational lifetime (LT50 = 40309 h) at initial luminance 100 cd m-2 . These results provide instructive guidance design device optimization energy-efficient stable HF-OLEDs high-quality light.

Language: Английский

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Thermally Activated Delayed Fluorescence with Nanosecond Emission Lifetimes and Minor Concentration Quenching: Achieving High‐Performance Nondoped and Doped Blue OLEDs

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(26)

Published: April 5, 2024

Simultaneously achieving a high photoluminescence quantum yield (PLQY), ultrashort exciton lifetime, and suppressed concentration quenching in thermally activated delayed fluorescence (TADF) materials is desirable yet challenging. Here, novel acceptor-donor-acceptor type TADF emitter, namely, 2BO-sQA, wherein two oxygen-bridged triarylboron (BO) acceptors are arranged with cofacial alignment positioned nearly orthogonal to the rigid dispirofluorene-quinolinoacridine (sQA) donor reported. This molecular design enables compound achieve highly efficient (PLQYs up 99%) short-lived (nanosecond-scale) blue effectively films. Consequently, doped organic light-emitting diodes (OLEDs) base on 2BO-sQA exceptional electroluminescence performance across broad range of doping concentrations, maintaining maximum external efficiencies (EQEs) at over 30% for concentrations ranging from 10 70 wt%. Remarkably, nondoped OLED achieves record-high EQE 26.6% small efficiency roll-off 14.0% 1000 candelas per square meter. By using as sensitizer multiresonance emitter ν-DABNA, TADF-sensitized OLEDs high-efficiency deep-blue emission. These results demonstrate feasibility this developing emitters efficiency, minimal quenching.

Language: Английский

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The Golden Age of Thermally Activated Delayed Fluorescence Materials: Design and Exploitation

Chemical Reviews, Journal Year: 2024, Volume and Issue: unknown

Published: Dec. 12, 2024

Since the seminal report by Adachi and co-workers in 2012, there has been a veritable explosion of interest design thermally activated delayed fluorescence (TADF) compounds, particularly as emitters for organic light-emitting diodes (OLEDs). With rapid advancements innovation materials design, efficiencies TADF OLEDs each primary color points well white devices now rival those state-of-the-art phosphorescent emitters. Beyond electroluminescent devices, compounds have also found increasing utility applications numerous related fields, from photocatalysis, to sensing, imaging beyond. Following our previous review 2017 (

Language: Английский

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Bright, efficient, and stable pure-green hyperfluorescent organic light-emitting diodes by judicious molecular design

Nature Communications, Journal Year: 2024, Volume and Issue: 15(1)

Published: April 12, 2024

Abstract To fulfill ultra-high-definition display, efficient and bright green organic light-emitting diodes with Commission Internationale de l’Éclairage y-coordinate ≥ 0.7 are required. Although there some preceding reports of highly devices based on pure-green multi-resonance emitters, the efficiency rolloff device stabilities for those still unsatisfactory. Herein, we report rational design two emitters achieving stable CIE x,y s that close to NTSC BT. 2020 standards. In this study, our thermally activated delayed fluorescence OLEDs result in y up 0.74. hyperfluorescent architecture, x further meet x-coordinate requirements, i.e., (0.21) (0.17), while keeping their ~ 0.7. Most importantly, display high maximum external quantum efficiencies over 25% luminance 10 5 cd m −2 suppressed rolloffs (external ~20% at 4 ) long LT 95 600 h.

Language: Английский

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Exploring Efficient Blue TADF Materials with Ultrafast Bipolar Charge Transport for High‐Efficiency Thick‐Layer OLEDs

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(30)

Published: March 26, 2024

Abstract Achieving strong solid‐state photoluminescence and fast charge transport simultaneously for organic molecules is of significant importance but challenging because the trade‐off between these properties. Herein, two tailored blue luminescent constructed with ring‐fused carbonyl‐containing electron acceptors spiro‐acridine donors are developed. Owing to ordered long‐range molecular alignment proper interaction energies, their neat films exhibit ultrafast bipolar delayed fluorescence high quantum yields short lifetimes. In doped light‐emitting diodes (OLEDs), both display eminent electroluminescence performances excellent external efficiencies (EQEs) 40.6%. They also brilliant lights record‐beating EQEs 30.2% in non‐doped thin‐layer OLEDs, more importantly, high‐performance simplified thick‐layer OLEDs achieved, rendering lowered driving voltages, best 23.0% tiny efficiency roll‐offs. addition, using them as sensitizers, remarkable 40.1% 23.2% ultrasmall roll‐offs realized hyperfluorescence respectively. The operational lifetimes obviously elongated matter devices or devices. This work provides promising candidates efficient opens a new avenue toward simultaneously.

Language: Английский

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Purely Organic Room‐Temperature Phosphorescence Molecule for High‐Performance Non‐Doped Organic Light‐Emitting Diodes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(29)

Published: April 30, 2024

Abstract Purely organic molecules with room‐temperature phosphorescence (RTP) are potential luminescent materials high exciton utilization for light‐emitting diodes (OLEDs), but those exhibiting superb electroluminescence (EL) performances rarely explored, mainly due to their long lifetimes. Herein, a robust purely RTP molecule, 3,6‐bis(5‐phenylindolo[3,2‐a]carbazol‐12(5H)‐yl)‐xanthen‐9‐one (3,2‐PIC‐XT), is developed. The neat film of 3,2‐PIC‐XT shows strong green very short lifetime (2.9 μs) and photoluminescence quantum yield (72 %), behaviors balanced bipolar charge transport. nature validated by steady‐state transient absorption emission spectroscopies, the working mechanism deciphered theoretical simulation. Non‐doped multilayer OLEDs using thin films furnish an outstanding external efficiency (EQE) 24.91 % extremely low roll‐off (1.6 %) at 1000 cd m −2 . High‐performance non‐doped top‐emitting tandem also achieved, providing remarkable EQEs 24.53 42.50 %, respectively. Delightfully, simplified employing thick realized, furnishing excellent EQE 17.79 greatly enhanced operational lifetime. temperature‐dependent EL spectroscopies demonstrate electrophosphorescence attribute 3,2‐PIC‐XT. These best devices based on reported so far.

Language: Английский

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Nitrogen Effects Endowed by Doping Electron-Withdrawing Nitrogen Atoms into Polycyclic Aromatic Hydrocarbon Fluorescence Emitters

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(23), P. 15977 - 15985

Published: May 7, 2024

Unveiling innovative mechanisms to design new highly efficient fluorescent materials and, thereby, fabricate high-performance organic light-emitting diodes (OLEDs) is a concerted endeavor in both academic and industrial circles. Polycyclic aromatic hydrocarbons (PAHs) have been widely used as emitters blue OLEDs, but device performances are far from satisfactory. In response, we propose the concept of "nitrogen effects" endowed by doping electron-withdrawing nitrogen atoms into PAH fluorescence emitters. The presence n orbital on imine conducive promoting electron coupling, which leads increased molar absorptivity an accelerated radiative decay rate emitters, thereby facilitating Förster energy transfer (FET) process OLEDs. Additionally, electronically withdrawing enhances host–guest interactions, positively affecting FET horizontal orientation factor emitting layer. To validate concept, cobalt-catalyzed multiple C–H annulation has utilized incorporate alkynes imine-based frameworks, enables various imine-embedded (IE-PAH) cyclization demonstrates notable regioselectivity, offering practical tool precisely introduce peripheral groups at desired positions with bulky alkyl units positioned adjacent atoms, were previously beyond reach through Friedel–Crafts reaction. Blue OLEDs fabricated IE-PAHs exhibit outstanding performance maximum external quantum efficiency (EQEmax) 32.7%. This achievement sets groundbreaking record for conventional PAH-based EQEmax 24.0%.

Language: Английский

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