Recent advances in the design of afterglow materials: mechanisms, structural regulation strategies and applications

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 52(22), P. 8005 - 8058

Published: Jan. 1, 2023

Afterglow materials have attracted widespread attention owing to their distinctive and long-lived optical emission properties which create exciting opportunities in various fields.

Language: Английский

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Carbazole‐Decorated Organoboron Emitters with Low‐Lying HOMO Levels for Solution‐Processed Narrowband Blue Hyperfluorescence OLED Devices

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(47)

Published: Sept. 30, 2023

The hyperfluorescence has drawn great attention in achieving efficient narrowband emitting devices based on multiple resonance thermally activated delayed fluorescence (MR-TADF) emitters. However, solution-processed pure blue is still a challenge, due to the unbalanced charge transport and serious exciton quenching caused by that holes are easily trapped high-lying HOMO (the highest occupied molecular orbital) level of traditional diphenylamine-decorated Here, we developed two organoboron emitters with low-lying levels decorating MR-TADF core weakly electron-donating carbazoles, which could suppress hole trapping effect reducing traps between host emitter from deep (0.40 eV) shallow (0.14/0.20 ones for facilitating formation, as well avoiding quenching. And large dihedral angle carbazole makes act steric hindrance inhibit aggregation. Accordingly, optimized simultaneously realize record external quantum efficiency 29.2 %, emission full-width at half-maximum 16.6 nm, color CIE coordinates (0.139, 0.189), best result organic light-emitting diodes

Language: Английский

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High‐Performance Narrowband OLED with Low Efficiency Roll‐Off Based on Sulfur‐Incorporated Organoboron Emitter

Advanced Optical Materials, Journal Year: 2023, Volume and Issue: 11(24)

Published: July 21, 2023

Abstract Multi‐resonance (MR) based organoboron emitters exhibiting high‐efficiency narrowband thermally activated delayed fluorescence (TADF) have become a critical material component for constructing high‐performance organic light‐emitting diodes (OLEDs) with high color purity and gamut. However, most of the MR‐TADF devices suffer from severe efficiency roll‐off at current density due to relatively large singlet–triplet splitting energy, long excited state lifetime, slow reverse intersystem crossing rate ( k RISC ). Herein, by utilizing sulfur atom‐fused donor unit, 7 H ‐benzo[4,5]thieno[2,3‐b]carbazole, an boron emitter (BTC‐BNCz) capable low TADF emission is developed. Benefitting heavy atom effect atom, up 1.6 × 10 5 s −1 achieved, which could greatly reduce undesired quenching effect. Consequently, OLED using BTC‐BNCz as dopant exhibits external quantum (EQE) 27.0% full width half maximum (FWHM) 35 nm. Moreover, horizontal dipole ratio assistant host, outstanding device performance achieved EQE 35.2% FWHM 37 nm, featuring roll‐off.

Language: Английский

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Trap-regulated highly efficient mechanoluminescence and persistent mechanoluminescence of Ca₂MgSi₂O₇:Eu²⁺

Journal of Materials Chemistry C, Journal Year: 2023, Volume and Issue: 11(34), P. 11509 - 11517

Published: Jan. 1, 2023

Mechanoluminescence and persistent mechanoluminescence were achieved in Ca 2 MgSi O 7 :Eu 2+ /epoxy composites, enhanced simultaneously by utilizing a trap-regulation strategy.

Language: Английский

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Highly Horizontal Oriented Tricomponent Exciplex Host with Multiple Reverse Intersystem Crossing Channels for High‐Performance Narrowband Electroluminescence and Eye‐Protection White Organic Light‐Emitting Diodes

Advanced Materials, Journal Year: 2024, Volume and Issue: 36(33)

Published: June 19, 2024

Despite multiple-resonance thermally activated delayed fluorescence (MR-TADF) emitters with small full-width at half maximum are attractive for wide color-gamut display and eye-protection lighting applications, their inefficient reverse intersystem crossing (RISC) process long exciton lifetime induce serious efficiency roll-off, which significantly limits development. Herein, a novel device concept of building highly efficient tricomponent exciplex multiple RISC channels is proposed to realize reduced quenching enhanced upconversion nonradiative triplet excitons, subsequently used as host high-performance MR-TADF organic light-emitting diodes (OLEDs). Compared traditional binary exciplex, the exhibits obviously improved photoluminescence quantum yield, emitting dipole orientation rate constant, record-breaking external (EQE) 30.4% achieved p-PhBCzPh: PO-T2T: DspiroAc-TRZ (50: 20: 30) based OLED. Remarkably, EQEs 36.2% 40.3% ultralow roll-off 26.1% 30.0% 1000 cd m

Language: Английский

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Synergistic Intramolecular Non‐Covalent Interactions Enable Robust Pure‐Blue TADF Emitters

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

Published: Sept. 17, 2024

Abstract Stability‐issues of organic light‐emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) require further advancements, especially in pure‐blue range CIE y < 0.20, existing a dilemma between color purity and device lifetime. Though improving bond‐dissociation‐energy (BDE) can effectively improve material intrinsic stability, strategies to simultaneously BDE photophysical performances are still lacking. Herein, it is disclosed that synergistic intramolecular non‐covalent interactions (Intra‐NI) achieve not only the highest C─N among blue TADF materials, but enhanced molecular‐rigidity, near‐unity photoluminescent quantum yields short Pure‐blue TADF‐OLEDs based on proof‐of‐concept realize high external‐quantum‐efficiency record‐high LT 80 @500 cd m −2 109 h with = 0.16. Furthermore, deep‐blue TADF‐sensitized devices exhibit 81 0.10. The findings provide new insight into critical role Intra‐NI OLED materials open way tackling vexing stability issues for developing robust emitters other functional materials.

Language: Английский

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Host Engineering of Deep‐Blue‐Fluorescent Organic Light‐Emitting Diodes with High Operational Stability and Narrowband Emission

Advanced Science, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 20, 2024

Abstract The realization of highly operationally stable blue organic light‐emitting diodes (OLEDs) is a challenge in both academia and industry. This paper describes the development anthracene–dibenzofuran host materials, 2‐(10‐(naphthalen‐1‐yl)anthracen‐9‐yl)naphtho[2,3‐b]benzofuran ( Host 1 ) 2‐(10‐([1,1′‐biphenyl]‐2‐yl)anthracen‐9‐yl)naphtho[2,3‐b]benzofuran 2 ), namely for use emissive layer an OLED stack. A multiple‐resonance thermally activated delayed serves as fluorescence emitter exhibits initial luminance 1000 cd m −2 long operational stability (i.e., time to decay 90% luminance) 249 h. Furthermore, deep‐blue with optimized top‐emitting architecture high current efficiency 154.3 −1 , fabricated calibrated Commission International de l’Éclairage y chromaticity coordinate 0.048. Moreover, emission spectrum this has narrowband peak at 476 nm full width half maximum (FWHM) 16 nm. work provides valuable insights into design anthracene‐based materials highlights importance optimization improving OLEDs.

Language: Английский

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Carbonyl Fused Organoboron Polycyclic Aromatic Hydrocarbon for Bathochromic‐Shifted Narrowband OLED

Advanced Optical Materials, Journal Year: 2023, Volume and Issue: 12(9)

Published: Dec. 21, 2023

Abstract Polycyclic aromatic hydrocarbon (PAH) compounds are prospective materials for highly efficient narrowband organic light‐emitting diodes. Specifically, boron‐nitrogen doped PAHs exhibit multiple resonance (MR) effect toward thermally activated delayed fluorescence (TADF) and narrow full width at half‐maximum (FWHM). Currently, the molecular design strategy bathochromic‐shifted MR‐TADF emitters is a hotspot challenging puzzle. Herein, carbonyl fused in PAH constructing boron/nitrogen/carbonyl emitter. Benefiting from carbonyl, developed emitter exhibits enhanced intramolecular charge transfer decreased reorganization energy, which displays emission pertinently. As consequence, proof‐of‐concept compound TCZBAO achieves an peak 522 nm FWHM of 39 nm, while carbonyl‐free TCZBAC 502 46 nm. Maximum external quantum efficiencies 36.1 % 32.4 realized devices based on TCZBAC, respectively, indicating guiding significance proposed developing emitters.

Language: Английский

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Fundamental understanding of nitrogen in biomass electrocatalysts for oxygen reduction and zinc-air batteries

iScience, Journal Year: 2024, Volume and Issue: 27(2), P. 108913 - 108913

Published: Jan. 16, 2024

Exploring high-efficiency catalysts for oxygen reduction reactions (ORRs) is essential the development of large-scale applications fuel cell and metal-air batteries technology. The as-prepared Fe-NC-800 via polymerization-pyrolysis strategy exhibited superior ORR activity with onset potential 1.030 V vs. reversible hydrogen electrode (RHE) half-wave 0.908 RHE, which higher than that Pt/C catalyst most other Fe-based catalysts. different d-band center values can be attributed to influence N-doped carbon, leading adjustment in activity. In addition, Fe-NC-800-based Zn-air battery showed better electrochemical performance a high discharge specific capacity 806 mA h g

Language: Английский

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Realizing Stable Narrowband Emission Blue Fluorescent Organic Light-Emitting Diodes with Dual-Channel Triplet Exciton Harvesting Host

The Journal of Physical Chemistry C, Journal Year: 2024, Volume and Issue: 128(12), P. 5330 - 5337

Published: March 14, 2024

Exciton annihilation is one of the main factors affecting operational lifetimes organic light-emitting diodes (OLEDs). Constructing an appropriate host–emitter system helpful in reducing exciton process and has a positive influence on stability device. Herein, "hot exciton" fluorescent material PAC with dual-channel triplet harvesting ability including reverse intersystem crossing from high-lying states triplet–triplet been explored as host narrowband multiresonance thermally activated delayed fluorescence blue emitter JBD-1 to achieve long device lifetime. The quenching alleviated by energy transfer long-lived excitons first state (T1) T1 PAC, leading lower defect formation rate more stable A lifetime LT50 = 458 h at initial luminance 1000 cd m–2, EQE 7.6%, Commission International de l'Eclairage coordinates (0.13, 0.11) were achieved bottom emission OLEDs, while devices based conventional hosts MCP MADN are only 0.37 1.09 h, respectively. This work suggests way for constructing OLEDs perspective host.

Language: Английский

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