Efficient Deep‐Blue Multiple‐Resonance Emitters Based on Azepine‐Decorated ν‐DABNA for CIE_y below 0.06

Advanced Materials, Год журнала: 2024, Номер 36(30)

Опубликована: Май 2, 2024

Abstract Ultrapure deep‐blue emitters are in high demand for organic light‐emitting diodes (OLEDs). Although color coordinates serve as straightforward parameters assessing purity, precise control over the maximum wavelength and full‐width at half‐maximum is necessary to optimize OLED performance, including luminance efficiency luminous efficacy. Multiple‐resonance (MR) promising candidates achieving ideal luminescence properties; consequently, a wide variety of MR frameworks have been developed. However, most these experience displacement from color, which limits their practical applicability. Therefore, molecular design that compatible with modulating energy levels output particularly valuable. Here, it demonstrated azepine donor unit induces an appropriate blue‐shift emission while maintaining efficient characteristics, photoluminescence quantum yield, narrow emission, fast reverse intersystem crossing rate. OLEDs using newly developed based on ν ‐DABNA framework simultaneously exhibit ≈30%, efficacy ≈20 lm W −1 , exceptional purity Commission Internationale de l’Éclairage low (0.14, 0.06), notably operational stability. These results demonstrate unprecedentedly compared those observed previously reported emitters.

Язык: Английский

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Excited‐State Engineering Enables Efficient Deep‐Blue Light‐Emitting Diodes Exhibiting BT.2020 Color Gamut

Advanced Materials, Год журнала: 2024, Номер 36(31)

Опубликована: Апрель 10, 2024

Organic luminescent materials that exhibit thermally activated delayed fluorescence (TADF) can convert non-emissive triplet excitons into emissive singlet states through a reverse intersystem crossing (RISC) process. Therefore, they have tremendous potential for applications in organic light-emitting diodes (OLEDs). However, with the development of ultra-high definition 4K/8K display technologies, designing efficient deep-blue TADF to achieve Commission Internationale de l'Éclairage (CIE) coordinates fulfilling BT.2020 remains significant challenge. Here, an effective approach is proposed design molecules based on hybrid long- and short-range charge-transfer by incorporation multiple donor moieties organoboron resonance acceptors. The resulting molecule exhibits emission at 414 nm full width half maximum (FWHM) 29 nm, together thousand-fold increase RISC rate. OLEDs champion material record external quantum efficiency (EQE) 22.8% CIE (0.163, 0.046), approaching blue standard. Moreover, TADF-assisted devices employing designed as sensitizer exceptional EQE 33.1%. This work thus provides blueprint future emitters, representing important milestone towards meeting color gamut standard BT.2020.

Язык: Английский

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Organic light-emitting transistors with high efficiency and narrow emission originating from intrinsic multiple-order microcavities

Nature Materials, Год журнала: 2025, Номер unknown

Опубликована: Март 28, 2025

Язык: Английский

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Indolocarbazole Derivatives for Highly Efficient Organic Light‐Emitting Diodes

Advanced Energy Materials, Год журнала: 2024, Номер unknown

Опубликована: Март 12, 2024

Abstract Since the discovery of organic light‐emitting diode (OLED), scientists worldwide have dedicated extensive efforts to enhance efficiency and reliability devices, striving for superior performance. Various molecular structures undergone structural modifications assess their suitability in achieving desired outcomes. This review focuses on indolo[3,2,1‐ jk ]carbazole (ICz), a building block that has garnered considerable attention within OLED community. The rigid fused ICz core induces multiresonance effect through an alternating distribution frontier orbitals. Notably, ICz‐based thermally activated delayed fluorescence emitters exhibit full width at half maximum below 20 nm, ensuring high color purity, boast external quantum above 30%, comparable state‐of‐the‐art narrow‐emitting boron–nitrogen‐type materials. Furthermore, is host metal complexes, enhancing stability, efficiency, purity. Consequently, promising as central component emitters, improving device aims succinctly summarize studies materials field, offering insights into future perspectives regarding developing applying ICz‐derived compounds.

Язык: Английский

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Peripheral Substitution Engineering of MR‐TADF Emitters Embedded With B‒N Covalent Bond Towards Efficient BT.2020 Blue Electroluminescence

Advanced Materials, Год журнала: 2024, Номер unknown

Опубликована: Окт. 15, 2024

Compared with the classical boron/nitrogen (B/N) doped ones, multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters embedded B-N covalent bond behave a significantly blue-shifted narrowband TADF, and thus show greater potential in ultrapure blue organic light-emitting diodes (OLEDs). As proof of concept, herein peripheral substitution engineering is demonstrated based on such B‒N parent core. The simple approach found to ensure easy synthesis via one-pot lithium-free borylation-annulation, manipulate excited states through different electronic coupling between core substituent, introduce steric hindrance minimize unwanted spectral broadening. Impressively, OLEDs are realized give high external quantum efficiency 20.3% together Commission Internationale de l'Éclairage coordinates (0.152, 0.046). performance well competent those B/N MR-TADF emitters, clearly highlighting that framework novel promising paradigm towards efficient BT.2020 standard.

Язык: Английский

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Enhancing Spin–Orbit Coupling in an Indolocarbazole Multiresonance Emitter by a Sulfur‐Containing Peripheral Substituent for a Fast Reverse Intersystem Crossing

Advanced Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 17, 2024

Abstract A fast reverse intersystem crossing (RISC) remains an ongoing pursuit for multiresonance (MR) emitters but faces formidable challenges, particularly indolocarbazole (ICz) derived ones. Here, heavy‐atom effect is introduced first to construct ICz‐MR emitter using a sulfur‐containing substitute, simultaneously enhancing both spin–orbit and spin–vibronic coupling afford RISC with rate of 1.2 × 10 5 s −1 , nearly one order magnitude higher than previous maximum values. The also exhibits extremely narrow deep‐blue emission peaking at 456 nm full‐width half‐maxima merely 12 photoluminescence quantum yield 92%. Benefiting from its efficient triplet upconversion capability, this achieves not only high external efficiency (EQE) 31.1% in organic light‐emitting diodes greatly alleviates roll‐off, affording record‐high EQEs 29.9% 1000 cd m −2 18.7% 5000 among devices emitters.

Язык: Английский

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Multifunctional oxadiazole-based ultraviolet-emitting materials used as hosts for multicolor phosphorescence

Chemical Science, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Novel ultraviolet to deep-blue emissions are achieved in three donor–acceptor materials with weak donors and regulated stacking. High efficiency, low roll-off long operational lifetimes obtained green, yellow red emissive PhOLEDs.

Язык: Английский

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High‐Performance Solution‐Processable Organic Light‐Emitting Diode Based on a Narrowband Near‐Ultraviolet and a Hot Exciton Strategy

Angewandte Chemie International Edition, Год журнала: 2024, Номер unknown

Опубликована: Дек. 3, 2024

Abstract Achieving high efficiency narrowband near‐ultraviolet (NUV) emitters in organic light emitting diode (OLED) is still a formidable challenge. Herein, proof‐of‐concept hybridized local and charge transfer (HLCT) molecule, named ICz‐BO, prepared characterized, which both multiresonant (MR) skeletons are integrated via conjugation connection. A slightly distorted structure weak intramolecular (CT) interaction between two MR subunits lead to high‐lying reverse intersystem crossing (h‐RISC) channel of T 6 → S 1 , also evidenced by experimental calculated results. Impressively, the ICz‐BO emitter exhibits outstanding NUV emission at 404 nm with full‐width half maximum 28 toluene solution. The solution processable OLED shows an excellent device performance recorded external quantum 12.01 %, concomitant extremely low y‐axis Commission Internationale de l’Éclairage (CIE y ) value 0.031. To best our knowledge, this highest reported for HLCT‐based NUV‐OLEDs date. This research proves that skeleton plays positive effect on hot exciton emitter, provides alternative paradigm developing high‐efficiency emitters.

Язык: Английский

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Efficient Deep‐Blue Organic Light‐Emitting Diodes Employing Doublet Sensitization

Advanced Materials, Год журнала: 2024, Номер 36(45)

Опубликована: Сен. 10, 2024

Abstract Fast and efficient exciton utilization is a crucial solution highly desirable for achieving high‐performance blue organic light‐emitting diodes (OLEDs). However, the rate efficiency of in traditional OLEDs, which employ fully closed‐shell materials as emitters, are inevitably limited by spin statistical limitations transition prohibition. Herein, new sensitization strategy, namely doublet‐sensitized fluorescence (DSF), proposed to realize deep‐blue electroluminescence. In DSF‐OLED, doublet‐emitting cerium(III) complex, Ce‐2, utilized sensitizer multi‐resonance thermally activated delayed emitter ν ‐DABNA. Experimental results reveal that holes electrons predominantly recombine on Ce‐2 form doublet excitons, subsequently transfer energy singlet state ‐DABNA via exceptionally fast (over 10 8 s −1 ) (≈100%) Förster resonance emission. Due circumvention spin‐flip DSF mechanism, near‐unit remarkably short residence time 1.36 µs achieved proof‐of‐concept achieves Commission Internationale de l'Eclairage coordinate (0.13, 0.14), high external quantum 30.0%, small roll‐off 14.7% at luminance 1000 cd m −2 . The device exhibits significantly improved operational stability compared with unsensitized reference device.

Язык: 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, Год журнала: 2024, Номер 45(8), С. 082402 - 082402

Опубликована: Авг. 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%.

Язык: Английский

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