Full-Color, Narrowband, and High-Efficiency Electroluminescence from Boron and Carbazole Embedded Polycyclic Heteroaromatics

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(46), P. 19468 - 19472

Published: Nov. 5, 2020

Herein, we demonstrate that the strategic implementation of electron-accepting tricoordinate boron and electron-donating carbazole subunits into polycyclic aromatic hydrocarbons (PAHs) produces a family attractive full-color luminophores can emit narrowband efficient thermally activated delayed fluorescence (TADF). A versatile modular design for these boron- carbazole-embedded PAHs facilitate systematic modulation their photophysical optoelectronic properties. Organic light-emitting diodes utilize as TADF emitters electroluminescence from blue to red, achieving high maximum external quantum efficiencies 29.3%, 31.8%, 22.0% blue, green, respectively.

Language: Английский

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Multiresonant Thermally Activated Delayed Fluorescence Emitters Based on Heteroatom‐Doped Nanographenes: Recent Advances and Prospects for Organic Light‐Emitting Diodes

Advanced Functional Materials, Journal Year: 2020, Volume and Issue: 30(33)

Published: May 27, 2020

Abstract Since the first report in 2015, multiresonant thermally activated delayed fluorescent (MR‐TADF) compounds, a subclass of TADF emitters based on heteroatom‐doped nanographene material, have come to fore as attractive hosts well for organic light‐emitting diodes (OLEDs). MR‐TADF compounds typically show very narrow‐band emission, high photoluminescence quantum yields, and small Δ E ST values, around 200 meV, coupled with chemical thermal stabilities. These materials properties translated into some best reported deep‐blue OLEDs. Here, detailed review their derivatives so far is presented. This comprehensively documents all focus synthesis, optoelectronic behavior, OLED performance. In addition, computational approaches are surveyed accurately model excited state these compounds.

Language: Английский

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Recent Advances in Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(1), P. 565 - 788

Published: Dec. 1, 2021

This review surveys recent progress in the chemistry of polycyclic heteroaromatic molecules with a focus on structural diversity and synthetic methodology. The article covers literature published during period 2016-2020, providing an update to our first this topic (

Language: Английский

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Multi‐Resonance Deep‐Red Emitters with Shallow Potential‐Energy Surfaces to Surpass Energy‐Gap Law**

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 60(37), P. 20498 - 20503

Published: July 28, 2021

Abstract Efficient organic emitters in the deep‐red region are rare due to “energy gap law”. Herein, multiple boron (B)‐ and nitrogen (N)‐atoms embedded polycyclic heteroaromatics featuring hybridized π‐bonding/ non‐bonding molecular orbitals constructed, providing a way overcome above luminescent boundary. The introduction of B‐phenyl‐B N‐phenyl‐N structures enhances electronic coupling those para‐positioned atoms, forming restricted π‐bonds on phenyl‐core for delocalized excited states thus narrow energy gap. mutually ortho‐positioned B‐ N‐atoms also induce multi‐resonance effect peripheral skeleton orbitals, creating shallow potential surfaces eliminate high‐frequency vibrational quenching. corresponding with peaks at 662 692 nm exhibit full‐width half‐maximums 38 nm, high radiative decay rates ca. 10 8 s −1 , ≈100 % photo‐luminescence quantum yields record‐high maximum external efficiencies 28 normal planar light‐emitting diode structure, simultaneously.

Language: Английский

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Constructing Charge‐Transfer Excited States Based on Frontier Molecular Orbital Engineering: Narrowband Green Electroluminescence with High Color Purity and Efficiency

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(40), P. 17442 - 17446

Published: June 13, 2020

Abstract The design and synthesis of organic materials with a narrow emission band in the longer wavelength region beyond 510 nm remain great challenge. For constructing narrowband green emitters, we propose unique molecular strategy based on frontier orbital engineering (FMOE), which can integrate advantages twisted donor–acceptor (D‐A) structure multiple resonance (MR) delayed fluorescence skeleton. Attaching an auxiliary donor to MR skeleton leads novel molecule D‐A characteristics. Importantly, remarkable red‐shift maximum spectrum are achieved simultaneously. target has been employed as emitter fabricate light‐emitting diodes (OLEDs) Commission Internationale de L'Eclairage (CIE) coordinates (0.23, 0.69) external quantum efficiency (EQE) 27.0 %.

Language: Английский

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Solution‐Processable Pure Green Thermally Activated Delayed Fluorescence Emitter Based on the Multiple Resonance Effect

Advanced Materials, Journal Year: 2020, Volume and Issue: 32(40)

Published: Aug. 31, 2020

Thermally activated delayed fluorescence (TADF) materials based on the multiple resonance (MR) effect are applied in organic light-emitting diodes (OLEDs), combining high color purity and efficiency. However, they not fabricated via solution-processing, which is an economical approach toward mass production of OLED displays. Here, a solution-processable MR-TADF material (OAB-ABP-1), with extended π-skeleton bulky substituents, designed. OAB-ABP-1 synthesized from commercially available starting four-step process involving one-shot double borylation. presents attractive photophysical properties, narrow emission band, photoluminescence quantum yield, small energy gap between S1 T1 , low activation for reverse intersystem crossing. These properties attributed to alternating localization highest occupied lowest unoccupied molecular orbitals induced by boron, nitrogen, oxygen atoms. Furthermore, facilitate charge recombination, two novel semiconducting polymers similar ionization potentials that use as interlayer emissive layer materials. A solution-processed device using aforementioned polymers; it exhibits pure green electroluminescence full-width at half-maximum external efficiency minimum roll-off.

Language: Английский

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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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Highly Efficient Electroluminescence from Narrowband Green Circularly Polarized Multiple Resonance Thermally Activated Delayed Fluorescence Enantiomers

Advanced Materials, Journal Year: 2021, Volume and Issue: 33(21)

Published: April 17, 2021

Abstract Purely organic fluorescent materials that concurrently exhibit high efficiency, narrowband emission, and circularly polarized luminescence (CPL) remain an unaddressed issue despite their promising applications in wide color gamut‐ 3D‐display. Herein, the CPL optical property multiple resonance (MR) effect induced thermally activated delayed fluorescence (MR‐TADF) emission are integrated with purity luminous efficiency together. Two pairs of highly efficient green CP‐MR‐TADF enantiomers, namely, ( R / S )‐OBN‐2CN‐BN )‐OBN‐4CN‐BN, developed. The enantiomer‐based light‐emitting diodes (OLEDs) pure narrow full‐width at half‐maximums (FWHMs) 30 33 nm, maximum external quantum efficiencies (EQEs) 29.4% 24.5%, clear electroluminescence (CPEL) signals dissymmetry factors g EL ) +1.43 × 10 −3 /−1.27 +4.60 −4 /−4.76 , respectively. This is first example a OLED exhibits CPEL signal, TADF concurrently.

Language: Английский

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Achieving Pure Green Electroluminescence with CIEy of 0.69 and EQE of 28.2% from an Aza‐Fused Multi‐Resonance Emitter

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(40), P. 17499 - 17503

Published: July 3, 2020

Abstract Pure green emitters are essential for realizing an ultrawide color gamut in next‐generation displays. Herein, by fusing the difficult‐to‐access aza‐aromatics onto B (boron)–N (nitrogen) skeleton, a hybridized multi‐resonance and charge transfer (HMCT) molecule AZA‐BN was successfully synthesized through effective one‐shot multiple cyclization method. shows pure fluorescence with photoluminance quantum yield of 99.7 %. The corresponding device exhibits maximum external efficiency power 28.2 % 121.7 lm W −1 , respectively, full width half (FWHM) merely 30 nm Commission Internationale de l'Eclairage (CIE) coordinate y 0.69, representing purest bottom‐emitting organic light‐emitting diode.

Language: Английский

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Carbazole‐Based DABNA Analogues as Highly Efficient Thermally Activated Delayed Fluorescence Materials for Narrowband Organic Light‐Emitting Diodes

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(6), P. 2882 - 2886

Published: Nov. 12, 2020

Abstract Carbazole‐based DABNA analogues ( CzDABNA s) were synthesized from triarylamine by regioselective one‐shot single and double borylation. The reaction proceeded selectively at the ortho position of carbazolyl group, where highest occupied molecular orbital is mainly localized owing to difference in electron‐donating abilities diarylamino groups. facile scalable method enabled synthesis s, exhibiting narrowband thermally activated delayed fluorescence with emission spectra ranging deep blue green. organic light‐emitting diode devices employing these products as emitters exhibited deep‐blue, sky‐blue, green high external quantum efficiencies 19.5, 21.8, 26.7 %, respectively.

Language: Английский

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