Efficient selenium-integrated TADF OLEDs with reduced roll-off

Nature Photonics, Journal Year: 2022, Volume and Issue: 16(11), P. 803 - 810

Published: Oct. 13, 2022

Language: Английский

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Quenching‐Resistant Multiresonance TADF Emitter Realizes 40% External Quantum Efficiency in Narrowband Electroluminescence at High Doping Level

Advanced Materials, Journal Year: 2021, Volume and Issue: 34(3)

Published: Nov. 12, 2021

Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters manifest great potential for organic light-emitting diodes (OLEDs) due to their high exciton-utilization efficiency and narrowband emission. Nonetheless, tendency toward self-quenching caused by strong interchromophore interactions would induce doping sensitivity deteriorate the device performances, effective strategy construct quenching-resistant without sacrifycing color purity is still be developed. By segregating planar MR-TADF skeleton using two bulky carbazolyl units, herein a highly emissive molecule with enhanced quenching resistance reported. The steric effect largely removes formation of detrimental excimers/aggregates, boosts performance corresponding devices maximum external quantum (EQEmax ) up 40.0% full width at half (FWHM) 25 nm, representative only example single OLED that can concurrently achieve narrow bandwidth EL surpassing 40% date. Even ratio 30 wt%, EQEmax retained 33.3% nearly unchanged emission spectrum. This work provides viable approach realize doping-insensitive extreme high-end displays.

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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B,N-Embedded Double Hetero[7]helicenes with Strong Chiroptical Responses in the Visible Light Region

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(43), P. 17958 - 17963

Published: Oct. 19, 2021

The development of helicene molecules with significant chiroptical responses covering a broad range the visible spectrum is highly desirable for chiral optoelectronic applications; however, their absorption dissymmetry factors (gabs) have been mostly lower than 0.01. In this work, we report unprecedented B,N-embedded double hetero[7]helicenes nonbonded B and N atoms, which exhibit excellent properties, such as strong activities from 300 to 700 nm, record high gabs up 0.033 in spectral range, tunable circularly polarized luminescence (CPL) red near-infrared regions (600-800 nm) photoluminescence quantum yields (PLQYs) 100%. As revealed by theoretical analyses, values are related separate molecular orbital distributions owing incorporation atoms. new type heterohelicenes opens an appealing avenue future exploitation high-performance materials.

Language: Английский

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Achieving Ultimate Narrowband and Ultrapure Blue Organic Light‐Emitting Diodes Based on Polycyclo‐Heteraborin Multi‐Resonance Delayed‐Fluorescence Emitters

Advanced Materials, Journal Year: 2021, Volume and Issue: 34(9)

Published: Dec. 8, 2021

To achieve an ultimate wide color gamut for ultrahigh-definition displays, there is great demand the development of organic light-emitting diodes (OLEDs) enabling monochromatic, ultrapure blue electroluminescence (EL). Herein, high-efficiency and OLEDs based on polycyclo-heteraborin multi-resonance thermally activated delayed fluorescence (MR-TADF) materials, BOBO-Z, BOBS-Z, BSBS-Z, are reported. The key to design present luminophores exquisite combination interplay multiple boron, nitrogen, oxygen, sulfur heteroatoms embedded in a fused polycyclic π-system. Comprehensive photophysical computational investigations this family MR-TADF materials reveal that systematic implementation chalcogen (oxygen sulfur) atoms can finely modulate emission while maintaining narrow bandwidth, as well spin-flipping rates between excited singlet triplet states. Consequently, BSBS-Z demonstrate narrowband EL emission, with peaks at 445-463 nm full width half maxima 18-23 nm, leading Commission Internationale de l'Éclairage-y coordinates range 0.04-0.08. Particularly, incorporating sulfur-doped BOBS-Z notably high maximum external quantum efficiencies 26.9% 26.8%, respectively, small efficiency roll-offs achieved concurrently.

Language: Английский

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Sterically Wrapped Multiple Resonance Fluorophors for Suppression of Concentration Quenching and Spectrum Broadening

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(2)

Published: Oct. 12, 2021

Multiple resonance (MR) emitters are promising for highly efficient organic light-emitting diodes (OLEDs) with narrowband emission; however, they still face intractable challenges concentration-caused emission quenching, exciton annihilation, and spectral broadening. In this study, sterically wrapped MR dopants a fluorescent core sandwiched by bulk substituents were developed to address the reducing intermolecular interactions. Consequently, high photo-luminance quantum yields of ≥90 % small full width at half maximums (FWHMs) ≤25 nm over wide range dopant concentrations (1-20 wt %) recorded. addition, we demonstrated that emitter can effectively suppress Dexter interaction when doped in thermally activated delayed fluorescence sensitizer, eliminating loss through triplet. Within above concentration range, optimal realizes remarkably maximum external efficiencies 36.3-37.2 %, identical FWHMs 24 nm, alleviated efficiency roll-offs OLEDs.

Language: Английский

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Ultrapure green organic light-emitting diodes based on highly distorted fused π-conjugated molecular design

Nature Photonics, Journal Year: 2023, Volume and Issue: 17(3), P. 280 - 285

Published: Jan. 9, 2023

Language: Английский

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High‐Performance Narrowband Pure‐Red OLEDs with External Quantum Efficiencies up to 36.1% and Ultralow Efficiency Roll‐Off

Advanced Materials, Journal Year: 2022, Volume and Issue: 34(29)

Published: May 19, 2022

High-color-purity blue and green organic light-emitting diodes (OLEDs) have been resolved thanks to the development of B/N-based polycyclic multiple resonance (MR) emitters. However, due derivatization limit B/N structures, design red MR emitters remains challenging. Herein, a series novel is reported by para-positioning N-π-N, O-π-O, B-π-B pairs onto benzene ring construct an central core. These can be facilely modularly synthesized, allowing for easy fine-tuning emission spectra peripheral groups. Moreover, these display excellent photophysical properties such as near-unity photoluminescence quantum yield (PLQY), fast radiative decay rate (kr ) up 7.4 × 107 s-1 , most importantly, narrowband with full-width at half-maximum (FWHM) 32 nm. Incorporating emitters, pure OLEDs sensitized phosphor realize state-of-the-art device performances external efficiency (EQE) exceeding 36%, ultralow roll-off (EQE high 25.1% brightness 50 000 cd m-2 ), ultrahigh over 130 together good lifetime.

Language: Английский

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One-Shot Synthesis of Expanded Heterohelicene Exhibiting Narrowband Thermally Activated Delayed Fluorescence

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 144(1), P. 106 - 112

Published: Dec. 23, 2021

An expanded heterohelicene consisting of three BN2-embedded [4]helicene subunits (V-DABNA-Mes) has been synthesized by one-shot triple borylation. The key to success is the excessive use boron tribromide in an autoclave. Based on multiple resonance effect and six nitrogen atoms, V-DABNA-Mes exhibited a narrowband sky-blue thermally activated delayed fluorescence with full width at half-maximum 16 nm. resonating π-extension minimized singlet-triplet energy gap enabled rapid reverse intersystem crossing rate constant 4.4 × 105 s-1. solution-processed organic light-emitting diode device, employed as emitter, emission 480 nm high external quantum efficiency 22.9%.

Language: Английский

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Fabrication of Circularly Polarized MR‐TADF Emitters with Asymmetrical Peripheral‐Lock Enhancing Helical B/N‐Doped Nanographenes

Advanced Materials, Journal Year: 2021, Volume and Issue: 34(1)

Published: Oct. 24, 2021

Circularly polarized thermally activated delayed fluorescence (CP-TADF) and multiple-resonance (MR-TADF), which exhibit novel circularly luminescence excellent color fidelity, respectively, have gained immense popularity. In this study, integrated CP-TADF MR-TADF (CPMR-TADF) are prepared by strategic design synthesis of asymmetrical peripherally locked enantiomers, separated denoted as (P,P″,P″)-/(M,M″,M″)-BN4 (P,P″,P″)-/(M,M″,M″)-BN5 TADF light (CPL) properties. As the entire molecular frame participates in frontier orbitals, resulting helical chirality (+)/(-)-BN4- (+)/(-)-BN5-based solution-processed organic light-emitting diodes (OLEDs) helps achieving a narrow full width at half maximum (FWHM) 49/49 48/48 nm high external quantum efficiency (EQE) 20.6%/19.0% 22.0%/26.5%, respectively. Importantly, unambiguous electroluminescence signals with dissymmetry factors (gEL ) +3.7 × 10-3 /-3.1 (BN4) +1.9 /-1.6 (BN5) obtained. The results indicate successful exploitation CPMR-TADF-emitter-based OLEDs to three characteristics: efficiency, purity, light.

Language: Английский

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