scholarly journals Adjusting White OLEDs with Yellow Light Emission Phosphor Dye and Ultrathin NPB Layer Structure

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Jun Wang ◽  
Weizhi Li
Keyword(s):  
Thin Layer ◽  
White Light ◽  
Power Efficiency ◽  
High Efficiency ◽  
Light Emission ◽  
Layer Structure ◽  
Emission Spectra ◽  
Device Structure ◽  
Phosphor Material ◽  
Light Emitting

High efficiency white organic light emission devices were demonstrated with phosphor material dye bis[2-(4-tertbutylphenyl)benzothiazolato-N,C2′]iridium (acetylacetonate) and ultrathin layer structure. The ultra thin layer be composed of 4,4′-bis[N-1-naphthyl-N-phenyl-amino]biphenyl (NPB) or 4,4′-N,N′-dicarbazole-biphenyl : NPB mixed layer with blue light emission. The emission spectra of devices could be adjusted by different phosphor doping concentrations and ultra thin layer structure. Warm white light emitting device could be obtained with 5 wt% doping concentration and power efficiency of 9.93 lm/W at 5 V. Pure white light with Commission Internationale de l'Eclairage (CIE) coordinates of (0.33, 0.30) and external quantum efficiency of 4.49% could be achieved with ultra thin layer device structure and 3 wt% phosphor doped device.

scholarly journals Phosphorescent Molecularly Doped Light-Emitting Diodes with Blended Polymer Host and Wide Emission Spectra

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Jun Wang ◽  
Jun Gou ◽  
Weizhi Li
Keyword(s):  
Power Efficiency ◽  
High Efficiency ◽  
Light Emission ◽  
Green Light ◽  
Emission Spectra ◽  
Iridium Complex ◽  
Light Emitting ◽  
Host Materials ◽  
Green Light Emission ◽  
Organic Devices

Stable green light emission and high efficiency organic devices with three polymer layers were fabricated using bis[2-(4′-tert-butylphenyl)-1-phenyl-1H-benzoimidazole-N,C2′] iridium(III) (acetylacetonate) doped in blended host materials. The 1 wt% doping concentration showed maximum luminance of 7841 cd/cm2at 25.6 V and maximum current efficiency of 9.95 cd/A at 17.2 V. The electroluminescence spectra of devices indicated two main peaks at 522 nm and 554 nm coming from phosphor dye and a full width at half maximum (FWHM) of 116 nm. The characteristics of using blended host, doping iridium complex, emission spectrum, and power efficiency of organic devices were investigated.

A high-efficiency white light-emitting lanthanide–organic framework assembled from 4,4′-oxybis(benzoic acid), 1,10-phenanthroline and oxalate

2014 ◽  
Vol 2 (43) ◽  
pp. 9073-9076 ◽  
Author(s):  
Dou Ma ◽  
Xia Li ◽  
Rui Huo
Keyword(s):  
Benzoic Acid ◽  
White Light ◽  
High Efficiency ◽  
Light Emission ◽  
White Light Emission ◽  
Light Emitting ◽  
Organic Framework

High-efficiency white light emission was developed through the Gd(iii)/Eu(iii)/Tb(iii) doped complex with 4,4′-oxybis(benzoic acid), 1,10-phenanthroline and oxalate.

The self-reduction synthesis and luminescent properties of Eu2+-Eu3+ activated BaZr0.2Si2O5.4 phosphors with white light emission for white light-emitting diodes

2018 ◽  
Vol 32 (04) ◽  
pp. 1850047 ◽  
Author(s):  
Jianlin Zhong ◽  
Lixin Yu ◽  
Songchu Li ◽  
Xiaoqin Man ◽  
Wei Sun
Keyword(s):  
White Light ◽  
Light Emission ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
White Light Emission ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Light Emitting ◽  
Broadband Emission ◽  
White Light Emitting Diodes

The BaZr[Formula: see text]Si2O[Formula: see text]: Eu[Formula: see text]/Eu[Formula: see text] phosphors were prepared with different concentrations of Eu2O3 by a self-reduction method under air condition. The X-ray diffraction and the photoluminescence properties of the prepared samples were analyzed. The emission spectra consisting of a broadband emission from the 4f[Formula: see text]5d transitions of Eu[Formula: see text] and sharp emissions from 5D0-7F[Formula: see text] (J = 0, 1, 2, 3, 4) transitions of Eu[Formula: see text] are observed. The different luminescent colors can be obtained and modulated by doping different concentrations of Eu2O3 and the white light emission can be observed as the concentration of europium is 6%.

Eu3+/Eu2+/Tb3+ co-activated single-phase Gd2O2S: A high-performance white light emitting phosphor for light emitting diode

2021 ◽  
Vol 11 (1) ◽  
pp. 54-62
Author(s):  
Jinpeng Xie ◽  
Bonan Liu ◽  
Qingtao Qong ◽  
Zhicheng Xu ◽  
Zhiqiang Jin ◽  
...  
Keyword(s):  
White Light ◽  
High Performance ◽  
Single Phase ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Energy Transfer Mechanism ◽  
Excitation Spectra ◽  
Phosphor Material ◽  
Light Emitting ◽  
Co Doped

In this work, we report Eu3+/Tb3+/Eu2+ co-activated Gd2O2 S as novel phosphor materials that can be effectively applied in the white-light emitting diode based on a near-UV chip with sensational performances. The luminescent properties and energy transfer mechanism have been thoroughly investigated. The as-prepared europium/terbium co-doped Gd2O2 S phosphors exhibit strong fluorescence with tunable color output under UV-vis light excitation. Furthermore, a high response to ultraviolet illumination of 398 nm wavelength was observed in the excitation spectra, indicating an excellent match with a light-emitting-diode chip in the dominant emissions. It is found that a tricolor (blue, green and red) emission band which results in a white light emission can be acquired when Eu3+, Eu2+ and Tb3+ ions are all co-doped into the single phase Gd2O2S, and an optimum ion doping level (10 at.% Eu and 0.7 at.% Tb) can effectively emit nearly pure white color photoluminescence with lifetime effectively tuned from 0.55 ms to 1.10 ms. The CIE (Commission International de I'Eclairage 1931 chromaticity) is X = 0.3507, Y = 0.3029. It is therefore expected that the newly found phosphor material with high-performance properties possess great potentials for the future advanced white LED applications.

Direct white light emission from a rare-earth-free aluminium–boron–carbon–oxynitride phosphor

2014 ◽  
Vol 2 (21) ◽  
pp. 4297-4303 ◽  
Author(s):  
T. Ogi ◽  
H. Iwasaki ◽  
A. B. D. Nandiyanto ◽  
F. Iskandar ◽  
W.-N. Wang ◽  
...  
Keyword(s):  
Rare Earth ◽  
White Light ◽  
Light Emission ◽  
Precursor Solution ◽  
White Light Emission ◽  
Phosphor Material ◽  
Light Emitting ◽  
Boron Carbon

A novel direct white light emitting phosphor material was prepared from rare-earth free precursor solution.

scholarly journals Solution-processed multilayer small-molecule light-emitting devices with high-efficiency white-light emission

2014 ◽  
Vol 5 (1) ◽  
Author(s):  
Naoya Aizawa ◽  
Yong-Jin Pu ◽  
Michitake Watanabe ◽  
Takayuki Chiba ◽  
Kazushige Ideta ◽  
...  
Keyword(s):  
Small Molecule ◽  
White Light ◽  
High Efficiency ◽  
Light Emission ◽  
White Light Emission ◽  
Solution Processed ◽  
Light Emitting ◽  
Light Emitting Devices

scholarly journals Fabrication and Characterization of a Light-Emitting Device Based on the CdS/ZnS Spherical Quantum Dots

2021 ◽  
Author(s):  
Kobra Hasanirokh ◽  
Asghar Asgari ◽  
Saber Mohammadi
Keyword(s):  
Quantum Dots ◽  
Current Density ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
Critical Factor ◽  
White Light Emission ◽  
Device Structure ◽  
Light Emitting ◽  
Particle Layer

Abstract In this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of ITO/ ZnO / QD / CBP/ MoO 3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

scholarly journals Fabrication of a light-emitting device based on the CdS/ZnS spherical quantum dots

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Kobra Hasanirokh ◽  
Asghar Asgari ◽  
Saber Mohammadi
Keyword(s):  
Quantum Dots ◽  
Current Density ◽  
White Light ◽  
Light Emission ◽  
Blue Emission ◽  
White Light Emission ◽  
Core Shell ◽  
Device Structure ◽  
Light Emitting ◽  
Particle Layer

AbstractIn this work, we focus on the colloidal quantum dot based light-emitting diodes (QD-LEDs) performance. First, we synthesize the spherical QDs with a CdS core that covered with a wider band gap II–VI semiconductor acting as a shell (ZnS). In order to synthesize this nano crystal QDs with structure of CdS/ZnS/CdS/ZnS, we use a reverse micelle process. These four-layer quantum well quantum dots (QWQDs) can generate the white light emission. The positional design of different layers i.e., core/shell QD emitters is a critical factor for white emissive devices. The blue emission generated by CdS core mixes with green/orange components originating from ZnS inner shell and creates an efficiency white light emission. Then, we fabricate a white-QDLED with a device structure of FTO/ ZnO / QD / CBP/ MoO3 / Al films. A thin film of CdS/ZnS/CdS/ZnS QDs is deposited by electrostatically assembled colloidal QD solutions. The experimental results show that the emission spectra of QDs and current density through the LED are controlled by varying the particle sizes. The peaks of absorbance and Photoluminescence (PL) spectrums for core/shell structures get the red shifted as the dot size increases. Furthermore, this QD-LED with a smaller nano particle layer has a higher current density.

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