Highly efficient solution-processable four-coordinate boron compound: A thermally activated delayed fluorescence emitter with short-lived phosphorescence for OLEDs with small efficiency roll-off

Chemical Engineering Journal, Journal Year: 2024, Volume and Issue: 483, P. 149221 - 149221

Published: Feb. 2, 2024

Language: Английский

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Purely Organic Room‐Temperature Phosphorescence Molecule for High‐Performance Non‐Doped Organic Light‐Emitting Diodes

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(29)

Published: April 30, 2024

Abstract Purely organic molecules with room‐temperature phosphorescence (RTP) are potential luminescent materials high exciton utilization for light‐emitting diodes (OLEDs), but those exhibiting superb electroluminescence (EL) performances rarely explored, mainly due to their long lifetimes. Herein, a robust purely RTP molecule, 3,6‐bis(5‐phenylindolo[3,2‐a]carbazol‐12(5H)‐yl)‐xanthen‐9‐one (3,2‐PIC‐XT), is developed. The neat film of 3,2‐PIC‐XT shows strong green very short lifetime (2.9 μs) and photoluminescence quantum yield (72 %), behaviors balanced bipolar charge transport. nature validated by steady‐state transient absorption emission spectroscopies, the working mechanism deciphered theoretical simulation. Non‐doped multilayer OLEDs using thin films furnish an outstanding external efficiency (EQE) 24.91 % extremely low roll‐off (1.6 %) at 1000 cd m −2 . High‐performance non‐doped top‐emitting tandem also achieved, providing remarkable EQEs 24.53 42.50 %, respectively. Delightfully, simplified employing thick realized, furnishing excellent EQE 17.79 greatly enhanced operational lifetime. temperature‐dependent EL spectroscopies demonstrate electrophosphorescence attribute 3,2‐PIC‐XT. These best devices based on reported so far.

Language: Английский

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Achieving Efficient Narrow-Spectrum Violet Organic Light-Emitting Diodes Based on Through-Space Charge Transfer Molecules

ACS Materials Letters, Journal Year: 2025, Volume and Issue: unknown, P. 457 - 464

Published: Jan. 3, 2025

Violet organic light-emitting diodes (OLEDs) hold promise for advanced applications, yet achieving simultaneously high efficiency and color purity remains challenging. This study presents a rational design of violet emitters by establishing through-space charge transfer (TSCT) framework that enhances high-level reverse intersystem crossing (hRISC) the effective utilization triplet excitons. Two TSCT emitters, BO-MX-ICz tBO-MX-ICz, are tailored with weak donor acceptor bridged 9,9-dimethylxanthene in face-to-face stacking arrangement. These show narrow photoluminescence (PL) efficiency. Their OLEDs exhibit high-color-purity electroluminescence (EL) peaks at 406 408 nm, full width half-maximum (fwhm) 25 maximum external quantum efficiencies (ηext,maxs) 4.61% 5.03%. Additionally, as hosts green multiresonance (MR) they deliver EL spectra excellent ηext,maxs up to 34.36%. molecular strategy could advance high-performance short-wavelength optoelectronic devices.

Language: Английский

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Time-Dependent Multicolor Afterglow from Dual Persistent Luminescence of Fluorescence and Phosphorescence in a UV-Cured Polyurethane Matrix

ACS Materials Letters, Journal Year: 2024, Volume and Issue: 6(4), P. 1371 - 1379

Published: March 11, 2024

It remains challenging to develop organic afterglow materials with a variable emission color and not single during decay. Herein, we developed kind of time-dependent multicolor polyurethane (PU) system whose can undergo four distinct changes within 1.0 s. The rapid UV-cured copolymerization pyrene-1-carboxylate derivative (PyC) poly(ε-caprolactone) (PCL) prepolymer ensured that the resulting PU systems possessed dual persistent luminescence phosphorescence at 626 nm lifetime over 200 ms delayed fluorescence (DF) 393 up 26 ms. Such big separation peaks (over 230 nm) is from aggregated dispersed states PyC resulted in an change purple, via orange yellow, green. By virtue such colorful change, plus preparation method, these have shown promising application triple-level information encryption anticounterfeiting.

Language: Английский

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Room-Temperature Phosphorescence from Bamboo Fibers and Designed Materials

ACS Materials Letters, Journal Year: 2025, Volume and Issue: unknown, P. 1119 - 1126

Published: Feb. 20, 2025

Language: Английский

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Purely organic room-temperature phosphorescence sensitizers for highly efficient hyperfluorescence OLEDs

Science Advances, Journal Year: 2025, Volume and Issue: 11(12)

Published: March 21, 2025

Multiresonance thermally activated delayed fluorescence (MR-TADF) emitters are promising candidates for organic light-emitting diodes (OLEDs) with high color quality. However, in most cases, noble metal–containing phosphors required as sensitizers MR-TADF to improve their electroluminescence (EL) performances, which may lead cost and environmental pollution. Herein, an efficient purely room-temperature phosphorescence (RTP) material, 3,2-PIC-TXT, fast radiation is developed. It not only exhibits impressive EL performances emitter outstanding external quantum efficiency (EQE) of 33.2%, higher than that Ir(ppy) 3 (25.2%), but also functions remarkably a sensitizer green (BN2, tCzphB-Ph, tCzphB-Fl). The hyperfluorescence OLEDs using 3,2-PIC-TXT provide ultrahigh EQEs 40.9 43.8%, superior those based on (37.0 38.0%), along superb purity excellent operational stability. These the best devices RTP materials reported so far.

Language: Английский

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Exploring Robust Delayed Fluorescence Materials via Structural Rigidification for Realizing Organic Light‐Emitting Diodes with High Efficiencies and Small Roll‐Offs

Small, Journal Year: 2023, Volume and Issue: 20(7)

Published: Oct. 12, 2023

Thermally activated delayed fluorescence (TADF) materials have been widely studied for the fabrication of high-performance organic light-emitting diodes (OLEDs), but serious efficiency roll-offs still remain unsolved in most cases. Herein, it is wish to report a series robust green TADF compounds containing rigid xanthenone acceptor and acridine-based spiro donors. The enhancement molecular rigidity not only endows with improved thermal stability also results reduced geometric vibrations thus lowered reorganization energies. These exhibit distinct merits high stabilities, excellent photoluminescence quantum efficiencies (96%-97%), large horizontal dipole orientation ratios (87.4%-92.1%) fast rates (1.4-1.5 × 10

Language: Английский

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Molecular Engineering Modulating the Singlet–Triplet Energy Splitting of Indolocarbazole-Based TADF Emitters Exhibiting AIE Properties for Nondoped Blue OLEDs with EQE of Nearly 20%

ACS Applied Materials & Interfaces, Journal Year: 2023, Volume and Issue: 15(51), P. 59643 - 59654

Published: Dec. 13, 2023

The development of efficient blue thermally activated delayed fluorescence (TADF) emitters with an aggregation-induced emission (AIE) nature, for the construction organic light-emitting diodes (OLEDs), is still insufficient. This can be attributed to challenges encountered in molecular design, including inherent trade-off between radiative decay and reverse intersystem crossing (RISC), as well small singlet-triplet energy splitting (ΔEST) requirement high photoluminescence quantum yields (ΦPL). Herein, we present design three highly TADF molecules AIE characteristics by combining π-extended donors different acceptors modulate differences electron-donating electron-withdrawing abilities. approach not only ensures efficiency suppressing close π-π stacking, weakening nonradiative relaxation, enhancing transition but also maintains equilibrium ratio triplet singlet excitons facilitating process RISC. These exhibit properties, featuring quick rates low rates. ΦPL these reached impressive 88%. Based on their excellent comprehensive performance, nondoped PICzPMO OLEDs achieved electroluminescence exhibiting maximum external (EQEmax) up 19.5%, while doped device a higher EQEmax 20.8%. work demonstrated that fusing large rigid acceptors, it possible regulate difference abilities, resulting ΔEST, ΦPL, fast RISC process, which feasible strategy designing molecules.

Language: Английский

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Highly Efficient Red/Near‐Infrared Phosphorescence from Doped Crystals

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 64(1)

Published: Aug. 23, 2024

Organic red/near-infrared (NIR) room temperature phosphorescence (RTP) materials with low toxicity and facile synthesis are highly sought after, particularly for applications in biotechnology encryption. However, achieving efficient red/NIR RTP emitters has been challenging due to the weak spin-orbit coupling of organics rapid nonradiative decay imposed by energy gap law. Here we demonstrate boosted quantum yields (Φ

Language: Английский

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Room Temperature Phosphorescence with Time-Resolved Color Changes by Tuning the Conformation of Polyheterocyclic Phenothiazine Derivatives through the Electronic Effect

ACS Materials Letters, Journal Year: 2024, Volume and Issue: 6(3), P. 943 - 953

Published: Feb. 13, 2024

The research on organic luminescent materials has attracted much attention for their wide applications. Generally, the molecular conformation is of great importance but often overlooked, regardless its packing in aggregated states and corresponding performance. In this work, relationship between electronic effect substituents thermodynamically stable phenothiazine derivatives explored first time. When substituent phenyl or a 3-position pyridyl group, quasi-equatorial (QE) conformer main thermo-stable conformation. At time, lone pair electrons 10-position nitrogen are stabilized by polyheterocyclic core, resulting formation large p-π-conjugated electron system. 2-pyridine 4-pyridine more easily electron-deficient pyridine system, another p-π conjugated conformation, namely quasi-axial (QA) conformer, formed. addition, effects two conformations photophysical properties investigated detail. It was found that emissive both singlet triplet largely affected Excitedly, based adjustable one molecule containing combined with 3D printing successfully applied to advanced anticounterfeiting time-resolved phosphorescence color changes.

Language: Английский

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