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

Chemical Society Reviews, Год журнала: 2023, Номер 52(22), С. 8005 - 8058

Опубликована: Янв. 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.

Язык: 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, Год журнала: 2023, Номер 62(47)

Опубликована: Сен. 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

Язык: Английский

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Premixed Exciplex Co‐Host for Constructing High‐Performance Organic Light‐Emitting Diodes

Advanced Functional Materials, Год журнала: 2025, Номер unknown

Опубликована: Янв. 23, 2025

Abstract Exciplex, characterized by intermolecular charge transfer and thermally activated delayed fluorescence (TADF) properties, plays a significant role in organic light‐emitting diodes (OLEDs), particularly as co‐hosts. The rapid rate of reverse intersystem crossing (RISC) balanced carrier mobility contribute to improved efficiency suppressive roll‐off at high current density. Despite these advantages, the fabrication devices using two‐component exciplexes is challenging, especially when emitting layers require simultaneous evaporation three or four materials from separate crucibles. To address this issue, pair premixed exciplex co‐hosts developed utilized co‐host for Ir(ppy) 3 . consistent performance continuous parallelly fabricated with same sample indicates long‐term stability stable ratio electron donor acceptor molecules. achieve maximum luminance over 250 000 cd m −2 , external quantum 21.9%, regardless 4.6% 10 along prolonged operational LT 95 (lifetime 95% initial luminance) 165 h density mA cm Further enhancement device observed through co‐doping multiple resonance TADF (MR‐TADF) material layer, underscoring potential industrial application.

Язык: Английский

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

Advanced Optical Materials, Год журнала: 2023, Номер 11(24)

Опубликована: Июль 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.

Язык: Английский

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

Journal of Materials Chemistry C, Год журнала: 2023, Номер 11(34), С. 11509 - 11517

Опубликована: Янв. 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.

Язык: 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, Год журнала: 2024, Номер 36(33)

Опубликована: Июнь 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

Язык: Английский

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

Advanced Materials, Год журнала: 2024, Номер unknown

Опубликована: Сен. 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.

Язык: Английский

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

Advanced Science, Год журнала: 2024, Номер unknown

Опубликована: Сен. 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.

Язык: Английский

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

Advanced Optical Materials, Год журнала: 2023, Номер 12(9)

Опубликована: Дек. 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.

Язык: Английский

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

iScience, Год журнала: 2024, Номер 27(2), С. 108913 - 108913

Опубликована: Янв. 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

Язык: Английский

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