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Journal ArticleDOI

Over 10% EQE Near-Infrared Electroluminescence Based on a Thermally Activated Delayed Fluorescence Emitter

TLDR
In this article, a wedge-shaped Dπ-A-π-D emitter with thermally activated delayed fluorescence property and a small single-triplet splitting (ΔEst) of 0.14 eV is presented.
Abstract
Significant effort has been made to develop novel material systems to improve the efficiency of near-infrared organic light-emitting diodes (NIR OLEDs). Of those, fluorescent chromophores are mostly studied because of their advantages in cost and tunability. However, it is still rare for fluorescent NIR emitters to present good color purities in the NIR range and to have high external quantum efficiency (EQE). Here, a wedge-shaped D-π-A-π-D emitter APDC-DTPA with thermally activated delayed fluorescence property and a small single-triplet splitting (ΔEst) of 0.14 eV is presented. The non-doped NIR device exhibits excellent performance with a maximum EQE of 2.19% and a peak wavelength of 777 nm. Remarkably, when 10 wt% of APDC-DTPA is doped in 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene host, an extremely high EQE of 10.19% with an emission peak of 693 nm is achieved. All these values represent the best result for NIR OLEDs based on a pure organic fluorescent emitter with similar device structure and color gamut.

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Citations
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Journal ArticleDOI

Symmetrical spirobi[xanthene] based locally asymmetrical phosphine oxide host for low-voltage-driven highly efficient white thermally activated delayed fluorescence diodes

TL;DR: In this paper, a symmetrical and orthogonal spirobi[xanthene] (SX) skeleton was constructed for full-thermally activated delayed fluorescence (TADF) white organic light-emitting diodes.
Journal ArticleDOI

Thermally Activated Delayed Fluorescent Dendrimers that Underpin High‐Efficiency Host‐Free Solution‐Processed Organic Light‐Emitting Diodes

TL;DR: In this paper , the design, synthesis, density functional theory (DFT) modeling, and photophysics of three triazine-based dendrimers, tBuCz2pTRZ, tBz2mTRZ and tBZ2m2p TRZ, are reported, which resolve the conflicting requirements of achieving simultaneously a small ΔEST and a large oscillator strength by incorporating both meta-and paraconnected donor dendrons about a central triazine acceptor.
Journal ArticleDOI

A sky-blue thermally activated delayed fluorescence emitter based on multimodified carbazole donor for efficient organic light-emitting diodes

TL;DR: In this paper, a sky-blue thermally activated delayed fluorescent (TADF) emitter based on 2-(9H-carbazol-9-yl)-7,7-dimethyl-5,7dihydroindeno[2,1-b] carbazole (DCF) as donor and 2,4-diphenyl-1,3,5-triazine as acceptor was developed.
References
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Journal ArticleDOI

Highly efficient organic light-emitting diodes from delayed fluorescence

TL;DR: A class of metal-free organic electroluminescent molecules in which the energy gap between the singlet and triplet excited states is minimized by design, thereby promoting highly efficient spin up-conversion from non-radiative triplet states to radiative singlet states while maintaining high radiative decay rates.
Journal ArticleDOI

Highly efficient blue electroluminescence based on thermally activated delayed fluorescence.

TL;DR: It is shown that a large delocalization of the highest occupied molecular orbital and lowest unoccupied molecular orbital in these charge-transfer compounds enhances the rate of radiative decay considerably by inducing a large oscillator strength even when there is a small overlap between the two wavefunctions.
Journal ArticleDOI

Sky-Blue Organic Light Emitting Diode with 37% External Quantum Efficiency Using Thermally Activated Delayed Fluorescence from Spiroacridine-Triazine Hybrid.

TL;DR: Extremely efficient sky-blue organic electroluminescence with external quantum efficiency of ≈37% is achieved in a conventional planar device structure using a highly efficient thermally activated delayed fluorescence emitter based on the spiroacridine-triazine hybrid.
Journal ArticleDOI

Anthraquinone-Based Intramolecular Charge-Transfer Compounds: Computational Molecular Design, Thermally Activated Delayed Fluorescence, and Highly Efficient Red Electroluminescence

TL;DR: It is demonstrated that increasing the distance between donor (D) and acceptor (A) in intramolecular-charge-transfer molecules is a promising strategy for simultaneously achieving small ΔE(ST) and large k(F), which is in good agreement with those predicted by corrected time-dependent density functional theory.
Journal ArticleDOI

Near‐Infrared Organic Compounds and Emerging Applications

TL;DR: This Focus Review describes the emerging class of near-infrared (NIR) organic compounds containing the conjugated polyene, polymethine, and donor-acceptor chromophores and exploration of their NIR-absorbing, Nir-fluorescence, and N IR-photosensitizing properties for potential applications in heat absorbers, solar cells, andNIR light-emitting diodes.
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