Strongly Luminescent Tungsten Emitters with Emission Quantum Yields of up to 84 %: TADF and High‐Efficiency Molecular Tungsten OLEDs

Tetraphosphine-supported PtAu3 cluster complexes display intense phosphorescence with quantum yields of over 90% in doped films. High-efficiency solution-processable OLEDs are successfully achieved with extremely small EQE roll-off at a practical brightness over 1000 cd m−2.

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One-Step Hydrothermal Synthesis of Yellow and Green Emitting Silicon Quantum Dots with Synergistic Effect

Nanomaterials ◽

10.3390/nano9030466 ◽

2019 ◽

Vol 9 (3) ◽

pp. 466

Author(s):

Zhixia Zhang ◽

Chunjin Wei ◽

Wenting Ma ◽

Jun Li ◽

Xincai Xiao ◽

...

Keyword(s):

Quantum Dots ◽

Synergistic Effect ◽

High Efficiency ◽

Synergistic Effects ◽

Biomedical Science ◽

Future Application ◽

Quantum Yields ◽

Silicon Quantum Dots ◽

Long Wavelength ◽

One Step

The concept of synergistic effects has been widely applied in many scientific fields such as in biomedical science and material chemistry, and has further attracted interest in the fields of both synthesis and application of nanomaterials. In this paper, we report the synthesis of long-wavelength emitting silicon quantum dots based on a one-step hydrothermal route with catechol (CC) and sodium citrate (Na-citrate) as a reducing agent pair, and N-[3-(trimethoxysilyl)propyl]ethylenediamine (DAMO) as silicon source. By controlling the reaction time, yellow-emitting silicon quantum dots and green-emitting silicon quantum dots were synthesized with quantum yields (QYs) of 29.4% and 38.3% respectively. The as-prepared silicon quantum dots were characterized by fluorescence (PL) spectrum, UV–visible spectrum, high resolution transmission electron microscope (HRTEM), Fourier transform infrared (FT-IR) spectrometry energy dispersive spectroscopy (EDS), and Zeta potential. With the aid of these methods, this paper further discussed how the optical performance and surface characteristics of the prepared quantum dots (QDs) influence the fluorescence mechanism. Meanwhile, the cell toxicity of the silicon quantum dots was tested by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium (MTT) bromide method, and its potential as a fluorescence ink explored. The silicon quantum dots exhibit a red-shift phenomenon in their fluorescence peak due to the participation of the carbonyl group during the synthesis. The high-efficiency and stable photoluminescence of the long-wavelength emitting silicon quantum dots prepared through a synergistic effect is of great value in their future application as novel optical materials in bioimaging, LED, and materials detection.

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High-efficiency fluorescent polyimides based on locally excited triarylamine-containing dianhydride moieties

Polymer Chemistry ◽

10.1039/c5py00883b ◽

2015 ◽

Vol 6 (29) ◽

pp. 5225-5232 ◽

Cited By ~ 19

Author(s):

Jia-Hao Wu ◽

Guey-Sheng Liou

Keyword(s):

High Efficiency ◽

Quantum Yields ◽

Locally Excited ◽

Solid Films ◽

Aliphatic Diamine ◽

Pl Intensity ◽

Tetracarboxylic Dianhydride

Three fluorescent polyimides (PIs) were readily synthesized from the polycondensation of triarylamine-based tetracarboxylic dianhydride monomers with aliphatic diamine. The PL intensity of solid films and nanofibers revealed high PL quantum yields of up to 32% and 35%, respectively.

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Strongly Luminescent Tungsten Emitters with Emission Quantum Yields of up to 84 %: TADF and High‐Efficiency Molecular Tungsten OLEDs

Angewandte Chemie International Edition ◽

10.1002/anie.201906698 ◽

2019 ◽

Vol 58 (42) ◽

pp. 14896-14900 ◽

Cited By ~ 11

Author(s):

Kaai‐Tung Chan ◽

Tsz‐Lung Lam ◽

Daohong Yu ◽

Lili Du ◽

David Lee Phillips ◽

...

Keyword(s):

High Efficiency ◽

Quantum Yields

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Rational design of high efficiency green to deep red/near-infrared emitting materials based on isomeric donor–acceptor chromophores

Journal of Materials Chemistry C ◽

10.1039/c8tc05383a ◽

2019 ◽

Vol 7 (7) ◽

pp. 1880-1887 ◽

Cited By ~ 11

Author(s):

Youming Zhang ◽

Zhao Chen ◽

Jun Song ◽

Junjie He ◽

Xin Wang ◽

...

Keyword(s):

Rational Design ◽

Near Infrared ◽

High Efficiency ◽

Quantum Yields ◽

Donor Acceptor

A family of chromophores with an isomeric donor–acceptor framework are synthesized, which show remarkably different emission wavelengths with high photoluminescence quantum yields and decent electroluminescent efficiencies.

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Enhancement of Photovoltaic Device Performance in Close-Packed Nanowire Excitonic Solar Cells by Förster Resonance Energy Transfer (FRET)

MRS Proceedings ◽

10.1557/proc-1208-o13-02 ◽

2009 ◽

Vol 1208 ◽

Author(s):

Karthik Shankar ◽

Sanghoon Kim ◽

Xinjian Feng ◽

Arash Mohammadpour ◽

Craig Alan Grimes

Keyword(s):

Solar Cells ◽

Spectral Range ◽

High Efficiency ◽

Nanowire Array ◽

Nile Red ◽

Molecular Structures ◽

Zinc Phthalocyanine ◽

Quantum Yields ◽

Excitonic Solar Cells ◽

Energy Acceptor

AbstractOur ability to fabricate close-packed single crystal rutile TiO2 nanowire arrays with average inter-wire distances of 5-10 nm allows us to create and control FRET-induced coupling effects, which can occur in this distance regime, in this architecture. We explored the use of such coupling to boost the performance of nanowire excitonic solar cells. Using Ru complex triplet dye N719 as the energy acceptor and fluorescent tetra tert-butyl substituted zinc phthalocyanine as the energy donor (see Fig. 1 for molecular structures), we obtained up to a four fold improvement in the quantum yield for red photons in the 660-690 nm spectral range. Similarly, by using a carboxylated unsymmetrical squaraine dye as the energy acceptor and highly fluorescent Nile Red dye as the donor (see Fig. 1 for molecular structures), we obtained 60% increased external quantum yields for photons in the 480-580 nm spectral range. For both systems, the use of FRET broadened spectral coverage and improved light harvesting. In this report, we also develop fundamental design principles in choosing donor-acceptor combinations for high efficiency FRET-enhanced solar cells in nanowire array architectures.

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High efficiency photoresist-free lithography of UO3 patterns from amorphous films of uranyl complexes

Journal of Materials Research ◽

10.1557/jmr.1998.0196 ◽

1998 ◽

Vol 13 (5) ◽

pp. 1379-1389 ◽

Cited By ~ 17

Author(s):

M. Gao ◽

Ross H. Hill

Keyword(s):

Uranium Oxide ◽

High Efficiency ◽

Optical Lithography ◽

Silicon Surfaces ◽

Quantum Yields ◽

Chain Reaction ◽

Amorphous Films ◽

Chain Reactions ◽

A Chain ◽

Primary Photochemical Reaction

The solid state photochemistry of uranyl carboxylate complexes is presented with the purpose of developing methods for optical lithography of uranium oxide films. These complexes of the general formula, UO2(OOCR)2 (R = i-C3H7, C5H11, CH2C6H5, CH2OC2H5, C2H4OC2H5), were all photosensitive as thin amorphous films. The primary photochemical reaction for each of these complexes was the extrusion of a CO2 from the ligand and the production of radicals which initiated a chain reaction. The nature of this chain reaction was dependent upon the identity of the organic substituents, R. In some cases the chain reaction required a photochemical step while others were entirely thermal in nature. Of importance are the potentially high quantum yields which can be associated with thermal chain reactions. Some of the systems presented here exhibit quantum yields in excess of 1. This process was shown to be compatible with optical lithography by the patterning of the uranium oxide product on silicon surfaces.

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Use of Hydroxyl Radical Yield to Investigate a Urea and Cobalt Modified TiO2 Photocatalyst Degrading Rhodamine B under UV and Visible Light

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.773.595 ◽

2013 ◽

Vol 773 ◽

pp. 595-600 ◽

Cited By ~ 2

Author(s):

Jyun Hong Shen ◽

Pei Chi Lu ◽

Jao Jia Horng

Keyword(s):

Visible Light ◽

Hydroxyl Radical ◽

Rhodamine B ◽

High Efficiency ◽

Fluorescence Probe ◽

Sol Gel ◽

Ultra Violet ◽

Quantum Yields ◽

Toc Removal ◽

Catalytic Experiment

Material modification of TiO2 photo-catalyst (NMTi) by doping urea and cobalt via sol-gel method was used to achieve high efficiency degradation of rhodamine B (RhB) under visible light (Vis). Although good removal (up to 42% of TOC removed) of RhB by Degussa P25 under ultra violet irradiation, P25 did not effectively degrade RhB (up to 14% TOC removed) under Vis. In the batch photo-catalytic experiment with Vis irradiation, the removal efficiencies of absorbance and TOC by NMTi were 28 and 30%. We used terephthalic acid as fluorescence probe to catch hydroxyl radical (OH) and calculated their quantum yields. The OH yields of NMTi with Vis irradiating was 8.91×10-6 while P25 of 2.65×10-6 (P25 of 1.44×10-5 and NMTi of 1.00×10-5 under UV). The OH yields of NMTi were higher than that of P25 under Vis, but otherwise under UV irradiation. Therefore, our new composited NMTi was more effective than P25 under Vis for both absorbance and TOC removal of RhB. It seemed possessed the application potential under Vis irradiation.

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Thulium Doped Phosphors Under VUV Excitation

MRS Proceedings ◽

10.1557/proc-1111-d08-04 ◽

2008 ◽

Vol 1111 ◽

Cited By ~ 1

Author(s):

Bernard Moine ◽

Léna Beauzamy ◽

Richard S. Meltzer

Keyword(s):

Excited States ◽

High Efficiency ◽

Emission Spectra ◽

Quantum Yields ◽

Relaxation Energy ◽

Fluorescent Lamps ◽

Emission Lifetime ◽

Plasma Display ◽

Quantum Cutting ◽

Single Material

AbstractDevelopment of highly efficient mercury free fluorescent lamps and plasma display panels has been a challenging task due to the need for a combination of phosphor properties that are difficult to obtain in a single material (high efficiency, short emission lifetime and weak sensitivity to aging process under VUV excitation). Quantum cutting mechanism is a way to improve the fluorescence efficacy. Here we describe quantum cutting involving pairs of Tm3+ ions in KY3F10. Efficient excitation in the vacuum UV is initiated to the 5d state of Tm3+. This is followed by a cross relaxation energy transfer (CRET) involving the excited ion in the 5d state and nearby Tm3+ in the ground state, producing a pair of Tm3+ in excited states of the 4f13 configuration. Both ions can then emit photons. The excitation and reflection spectra are studied as a function of Tm3+ concentration and temperature. An unusual enhancement of the reflectivity at excitation wavelengths corresponding to the Tm3+ 5d absorption peaks is shown to arise from strong 5d→4f emission which is confirmed from the VUV emission spectra. The strong reduction of the integrated 5d emission intensity and shortening of its lifetime with Tm3+ concentration indicates the effective presence of the desired CRET process that is required for the first step of the quantum cutting. High Tm3+ concentrations are required for efficient quantum cutting. Whereas the CRET from the 5d state is estimated to be quite efficient, the 4f13 states of Tm3+ also undergo a strong CRET and therefore, emission from the 4f13 excited states that are created from the first step are strongly quenched at high Tm3+ concentrations. As a result, quantum yields greater than unity are not achieved.

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Спектроскопические свойства полимерных пленок, активированных супрамолекулярным наноалмазным комплексом европия с батофенантролином

Журнал технической физики ◽

10.21883/os.2019.08.48035.370-18 ◽

2019 ◽

Vol 127 (8) ◽

pp. 236

Author(s):

В.А. Лапина ◽

Т.А. Павич ◽

П.П. Першукевич

Keyword(s):

Emission Band ◽

High Efficiency ◽

Matrix Material ◽

Quantum Yields ◽

Excitation Spectra ◽

Light Emitting ◽

Light Emitting Devices ◽

Luminescent Films ◽

Laser Media ◽

Main Emission Band

For the first time, using the supramolecular diamond-containing europium (III) complex with bathophenanthroline, new luminescent films were obtained, converting UV radiation in the wavelength range of 220–410 nm with high efficiency to luminescence of europium ions, with the ability to control the degree of monochromaticity of radiation in the main emission band of Eu3+ ions with maximum of 615 nm. It was found that the shape of the excitation spectra, the half-width of the main emission band of 615 nm (transition 5D0–7F2), the values of quantum yields (within ~ 0.3–0.8) depend on the type of matrix material. The proposed optical materials can be used in the development of various light-emitting devices: screens, indicators, solar concentrators, organic light-emitting diodes, laser media.

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