Planar Expansion Enhances Horizontal Orientation of Multi‐Resonance TADF Emitter Toward Highly Efficient Narrowband Blue OLEDs

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: 34(49)

Published: Aug. 8, 2024

Abstract Multi‐resonance thermally activated delayed fluorescence (MR‐TADF) materials are of vital importance for ultra‐high‐definition displays. However, developing molecular design tactics blue MR‐TADF emitters that simultaneously achieve good TADF properties, narrowband emission, and ideal orientation remains challenging. Here, an effective approach to enhance the electroluminescent (EL) performance emitter by enlarging planar through a peripheral decoration strategy is presented. The resulting proof‐of‐concept emitter, 3QCzBN, not only exhibits emission with narrow full‐width at half maximum (FWHM) 22 nm, but also remarkable photoluminescent quantum yield (PLQY) 98%. Together accelerated reverse intersystem crossing (RISC) processes nearly perfect horizontal ratios emitting dipole (Θ // ) 98% compared its parent MR molecule, organic light‐emitting diodes (OLEDs) based on 3QCzBN demonstrate color purity outstanding external efficiency (EQE max 34.8% low roll‐off.

Language: Английский

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Regional Functionalization Molecular Design Strategy: A Key to Enhancing the Efficiency of Multi‐Resonance OLEDs

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(38)

Published: July 6, 2024

Herein, we propose a regional functionalization molecular design strategy that enables independent control of distinct pivotal parameters through different molecule segments. Three novel multiple resonances thermally activated delayed fluorescence (MR-TADF) emitters A-BN, DA-BN, and A-DBN, have been successfully synthesized by integrating highly rigid three-dimensional adamantane-containing spirofluorene units into the MR framework. These molecules form two distinctive functional parts: part 1 comprises boron-nitrogen (BN)-MR framework with adjacent benzene fluorene forming central luminescent core characterized an exceptionally planar geometry, allowing for narrow FWHM values; 2 includes peripheral mesitylene, benzene, adamantyl groups, creating unique "umbrella-like" conformation to mitigate intermolecular interactions suppress exciton annihilation. The resulting A-DBN exhibit remarkably values ranging from 18 14 nm near-unity photoluminescence quantum yields. Particularly, OLEDs based on DA-BN demonstrate outstanding efficiencies 35.0 % 34.3 %, as low 22 25 nm, respectively, effectively accomplishing integration high color purity device performance.

Language: Английский

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Peripheral carbazole units-decorated MR emitter containing B−N covalent bond for highly efficient green OLEDs with low roll-off

Journal of Semiconductors, Journal Year: 2024, Volume and Issue: 45(8), P. 082402 - 082402

Published: Aug. 1, 2024

Abstract Boron−nitrogen doped multiple resonance (BN-MR) emitters, characterized by B−N covalent bonds, offer distinctive advantages as pivotal building blocks for facile access to novel MR emitters featuring narrowband spectra and high efficiency. However, there remains a scarcity of exploration concerning synthetic methods structural derivations expand the library BN-MR emitters. Herein, we present synthesis emitter, t Cz[B−N]N, through one-pot borylation reaction directed amine group, achieving an impressive yield 94%. The emitter is decorated incorporating two 3,6-di-t-butylcarbazole ( Cz) units into bond parent molecule via para -C−π−D -N−π−D conjugations. This peripheral decoration strategy enhances reverse intersystem crossing process shifts emission band towards pure green region, peaking at 526 nm with full-width half maximum (FWHM) 41 nm. Consequently, organic light emitting diodes (OLEDs) employing this achieved external quantum efficiency (EQE max ) value 27.7%, minimal roll-off. Even practical luminance 1000 cd∙m −2 , device maintains EQE 24.6%.

Language: Английский

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Manipulating photophysical properties through asymmetric modification of triptycene‐fused multi‐resonance TADF emitter

Bulletin of the Korean Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 16, 2025

Abstract Developing multi‐resonance (MR) effect‐induced thermally activated delayed fluorescence (TADF) emitters that exhibit excellent photophysical properties and a sterically shielded structure is crucial for achieving high‐efficiency stable organic light‐emitting diodes (OLEDs). Herein, we propose new synthetic approach to asymmetric bulky MR‐TADF based on B,N core. Three Tp‐fused MR ( 1 – 3 ) are produced by attaching rigid triptycene (Tp) moiety one side of the core introducing different N ‐containing functional groups other side. All high photoluminescence quantum yield, narrow full width at half maximum, TADF with reasonable reverse intersystem crossing rates (~10 4 s −1 in matrix. Notably, emission color ranges from deep blue sky blue, depending groups. Electrochemical theoretical studies further demonstrate frontier molecular orbitals distributed over formed two moieties, resulting energy levels vary accordingly. The findings this study will be useful design various color‐tunable yet emitters.

Language: Английский

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Bifunctional Group Modulation Strategy Enables MR‐TADF Electroluminescence Toward BT.2020 Green Light Standard

Advanced Materials, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 23, 2025

Abstract Herein, a parallel “bifunctional group” modulation method is proposed to achieve controlled of the emission wavelength and full‐width at half‐maximum (FWHM) values. As result, three proof‐of‐concept emitters, namely DBNDS‐TPh, DBNDS‐DFPh, DBNDS‐CNPh, are designed synthesized, with first functional dibenzo[ b,d ]thiophene unit concurrently reducing bandgap elevate their triplet state energy. A second group 1 , ′: 3 ′, ″‐ triphenyl electron acceptors 1,3‐difluorobenzene benzonitrile respectively, deepen HOMO LUMO levels. Accordingly, CIE coordinates DBNDS‐CNPh (0.13, 0.77), (0.14, 0.76) in dilute toluene solution. This marks instance achieving y value 0.77 solutions. Significantly, non‐sensitized pure‐green OLEDs based on DBNDS‐TPh DBNDS‐DFPh demonstrate peak EQE 35.0% 34.5%, corresponding (0.18, 0.75), (0.17, doping concentration wt.%, representing green OLED reaching 0.76 bottom‐emitting device structure as reported literature.

Language: Английский

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1,4-Azaborine Participation Enables Inaccessible Cycloarene with Unique Photophysical Properties

Journal of the American Chemical Society, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 26, 2025

Cycloarenes and heterocycloarenes, characterized by fused macrocyclic π-conjugated structures, hold significant promise in synthetic chemistry materials science. However, their further development remains constrained formidable challenges, particularly for those with contracted cavities. Inspired advances the synthesis of organoboron-based multiresonance thermally activated delayed fluorescence (TADF) emitters, we herein report convenient access detailed characterization a 1,4-azaborine-embedded cycloarene that features smallest cavity among known (hetero)cycloarenes. The induces bowl-shaped molecular geometry, as confirmed crystallographic analysis, while also triggering through-space conjugation delocalized π-electrons at site. Comparative studies between this compound its helical analogue reveal substantial topological impact on photophysical properties, including bathochromic-shifted broadened emission band, prolonged radiative decay process, more efficient triplet-to-singlet spin-flip. Capitalizing TADF remarkably high quantum yield, successfully fabricated first (hetero)cycloarene-based organic light-emitting diodes, achieving over 30% external efficiency minimal roll-off. These findings offer new insights into design topologically distinct compounds unique properties.

Language: Английский

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High‐Temperature‐Induced Fused Polycyclic Aromatic Multiple Resonance Emitters Exhibiting Narrowband and Pronounced Red‐Shifted Emission

Small, Journal Year: 2025, Volume and Issue: unknown

Published: March 10, 2025

Synthetic methodology is a fundamental framework for preparing functional materials, significantly advancing their development. Herein, novel 6π electrocyclization reaction unexpectedly discovered that promotes further ring closure in materials derived from multi-resonance thermally activated delayed fluorescence (MR-TADF) compounds, known narrow emission. By simply raising the temperature, this process red-shifts emission peak of target material while effectively narrowing its emissive width and greatly enhancing optoelectronic performance. Utilizing method, newly synthesized MR-TADF substrate GCz-4B2 successfully converted into compound GCz-4B1. Compared to GCz-4B2, GCz-4B1 exhibited redshift 26 nm concurrently achieving significant reduction full at half-maximum (FWHM) value corresponding shoulder intensity. Notably, photoluminescence quantum yield (PLQY) reached 95.1%, compared only 85.6% GCz-4B2. This enhancement can be attributed increased rigidity reaction, which reduced unfavorable vibrational relaxation processes improved PLQY values. Furthermore, OLEDs based on attained maximum external efficiency (EQEmax) 28.0%, with small FWHM 19.4 nm, surpassing devices

Language: Английский

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多硼效应实现高效率窄谱带蓝光OLED研究进展（特邀）

Published: Jan. 1, 2025

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Comprehensive Review on the Structural Diversity and Versatility of Multi-Resonance Fluorescence Emitters: Advance, Challenges, and Prospects toward OLEDs

Chemical Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: May 9, 2025

Fluorescence emitters with a multiple-resonant (MR) effect have become research hotspot. These MR mainly consist of polycyclic aromatic hydrocarbons boron/nitrogen, nitrogen/carbonyl, and indolocarbazole frameworks. The staggered arrangement the highest occupied molecular orbital lowest unoccupied facilitates MR, resulting in smaller internal reorganization energy narrower emission bandwidth. Optimal charge separation suppresses gap between singlet triplet excited states, favoring thermally activated delayed fluorescence (TADF). MR-TADF materials, due to color purity high efficiency, are excellent candidates for organic light-emitting diodes. Nevertheless, significant challenges remain; particular, limitation imposed by alternated core configuration hinders their diversity versatility. Most existing materials concentrated blue-green range, only few red near-infrared spectra. This review provides timely comprehensive screening from pioneering work present. Our goal is gain understandings structure-performance relationship both basic advanced perspectives. Special emphasis placed on exploring correlations chemical structure, photophysical properties electroluminescent performance depth breadth an aim promote future development emitters.

Language: Английский

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Simple‐Structure and Anti‐Quenching Deep‐Blue Multi‐Resonance TADF Emitters Enable High‐Efficiency OLEDs with BT.2020 Blue Gamut

Advanced Functional Materials, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 8, 2024

Abstract Developing highly efficient pure‐blue organic light‐emitting diodes (OLEDs) that meet the stringent BT.2020 standard by using multi‐resonance thermally activated delayed fluorescence (MR‐TADF) materials has long been a formidable challenge. In this study, strategy is demonstrated for high‐performance blue MR‐TADF emitters gradually decorating MR framework with alkyl groups, and subsequently introducing diarylamino group at para ‐position of boron atom. The proof‐of‐concept molecule, IPrBN‐mCP, exhibits narrowband deep‐blue emission peaking 452 nm, very narrow full‐width half maximum (FWHM) 19 nm in solution, remarkably high photoluminescence quantum yield (PLQY) approaching unity doped films. As result, OLEDs based on IPrBN‐mCP achieve not only external efficiency (EQE max ) 33.4% but also ultrapure Commission Internationale de L'Eclairage (CIE) y value 0.046, fully satisfying standard. This represents first OLED example meeting rigorous color requirements while simultaneously achieving an EQE exceeding 30%.

Language: Английский

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