scholarly journals Sr2−xBaxTiO4:Eu3+, Gd3+: A Novel Blue Converting Yellow-Emitting Phosphor for White Light-Emitting Diodes

2015 ◽  
Vol 2015 ◽  
pp. 1-5
Author(s):  
Limin Dong ◽  
Jiatong Zhao ◽  
Qin Li ◽  
Zhidong Han
Keyword(s):  
Blue Light ◽  
White Light ◽  
Single Phase ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Excitation Wavelength ◽  
Light Emitting ◽  
Gel Method ◽  
White Light Emitting Diodes

A highly intense yellow-emitting phosphorSr2-xBaxTiO4:Eu3+,Gd3+peaking at 593–611 nm was synthesized by the sol-gel method. XRD and SEM show that the samples are single phase and have irregular shape. The excitation wavelength matches well with that of the emission of the blue-light-emitting diode. The emission peaks at 593 and 611 nm are attributed to the transitions from the5D0-7F1and5D0-7F2ofEu3+ions, respectively.Gd3+was used as sensitizer, aiming at increasing the luminous intensity. A certain amount ofSr2+andBa2+is contributed to the intensity of light emission.

A promising red-emitting phosphor for white light emitting diodes prepared by sol–gel method

2008 ◽  
Vol 133 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Chongfeng Guo ◽  
Wei Zhang ◽  
Lin Luan ◽  
Tao Chen ◽  
Hong Cheng ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Sol Gel ◽  
Light Emitting ◽  
Gel Method ◽  
Sol Gel Method ◽  
White Light Emitting Diodes ◽  
Red Emitting Phosphor

A Single-Phase Full-Color Ca4Si2O7F2:Ce3+, Tb3+, Sm3+ Micron Belt Mat for White-Light Emitting Diode Application

2016 ◽  
Vol 697 ◽  
pp. 727-732 ◽  
Author(s):  
Bo Cui ◽  
Qing Hong Zhang ◽  
Hong Zhi Wang ◽  
Yao Gang Li
Keyword(s):  
Heat Treatment ◽  
White Light ◽  
Single Phase ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Electrospinning Process ◽  
Light Emitting ◽  
Full Color ◽  
Color Tunable ◽  
White Light Emitting Diodes

A new kind of Ca4Si2O7F2:Ce3+, Tb3+, Sm3+ oxyfluoride phosphor micron belt mat was obatained by simply electrospinning process and subsequent heat treatment. XRD result shows that a pure Ca4Si2O7F2 phase can be obtained at low temperature of around 900 °C. The micron belt precursor has a smooth surface and uniform morphology, and the width and thickness of the belt is about 2 μm and 200 nm. The morphology of micron belt is well retained after heat treatment, forming a plat phosphor mat consisting of uniform micron belt network. Ca4Si2O7F2:Ce3+, Ca4Si2O7F2:Tb3+, and Ca4Si2O7F2:Sm3+ exhibit the characteristic emissions of Ce3+ (4f7→4f65d1, blue), Tb3+ (4f8→4f75d, green), and Sm3+ (4f6→4f65d, red) under the excitation of near-UV light, respectively. By adjusting the doping concentration of Ce3+, Tb3+, Sm3+ ions a white emission in a single phase was obtained under the excitation of 360 nm. We have demonstrated that Ca4Si2O7F2:Ce3+, Tb3+, Sm3+ phosphor mat can be a promising candidate for a color-tunable phosphor mat applied in a near-UV White light emitting diodes.

Improved Yellow Light Emission in the Achievement of Dichromatic White Light Emitting Diodes

2013 ◽  
Vol 1538 ◽  
pp. 371-375
Author(s):  
Zhao Si ◽  
Tongbo Wei ◽  
Jun Ma ◽  
Ning Zhang ◽  
Zhe Liu ◽  
...  
Keyword(s):  
Blue Light ◽  
White Light ◽  
Light Emitting Diodes ◽  
Light Emission ◽  
Dual Wavelength ◽  
Emission Wavelength ◽  
White Led ◽  
Yellow Light ◽  
Light Emitting ◽  
White Light Emitting Diodes

ABSTRACTA study about the achievement of dichromatic white light-emitting diodes (LEDs) was performed. A series of dual wavelength LEDs with different last quantum-well (LQW) structure were fabricated. The bottom seven blue light QWs (close to n-GaN layer) of the four samples were the same. The LQW of sample A was 3 nm, and that of sample B, C and D were 6 nm, a special high In content ultra-thin layer was inserted in the middle of the LQW of sample C and on top of that of sample D. XRD results showed In concentration fluctuation and good interface quality of the four samples. PL measurements showed dual wavelength emitting, the blue light peak position of the four samples were almost the same, sample A with a narrower LQW showed an emission wavelength much shorter than that of sample B, C, D. EL measurement was done at an injection current of 100 mA. Sample A only showed LQW emission due to holes distribution. Because of wider LQW, the emission wavelength of sample B, C and D was longer and peak intensity was weaker. Sample D with insert layer on top of LQW showed strongest yellow light emission with a blue peak. As the injection current increased, sample A showed highest output light power due to narrower LQW. Of the other three samples with wider LQW, sample D showed highest output power. Effective yellow light emission has always been an obstacle to the achievement of dichromatic white LED. Sample D with insert layer close to p-GaN can confine the hole distribution more effectively hence the recombination of holes and electrons was enhanced, the yellow light emission was improved and dichromatic white LED was achieved.

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.

A potential green-emitting phosphor Ca8Mg(SiO4)4Cl2:Eu2+ for white light emitting diodes prepared by sol–gel method

2011 ◽  
Vol 257 (21) ◽  
pp. 8836-8839 ◽  
Author(s):  
Chongfeng Guo ◽  
Ming Li ◽  
Yan Xu ◽  
Ting Li ◽  
Zhaoyu Ren ◽  
...  
Keyword(s):  
White Light ◽  
Light Emitting Diodes ◽  
Sol Gel ◽  
Light Emitting ◽  
Gel Method ◽  
Sol Gel Method ◽  
White Light Emitting Diodes

Stable CsPbX3@SiO2 Perovskite Quantum Dots for White-Light Emitting Diodes

2020 ◽  
Vol 15 (5) ◽  
pp. 599-606
Author(s):  
Jian Xu ◽  
Hongxiang Zhang ◽  
Chunxia Wu ◽  
Jun Dai
Keyword(s):  
Quantum Dots ◽  
White Light ◽  
Light Emission ◽  
Light Emitting Diode ◽  
Synthesis Method ◽  
Water Contact ◽  
Light Emitting ◽  
Perovskite Quantum Dots ◽  
The Stability ◽  
White Light Emitting Diodes

In this article, we reported the synthesis method of stable CsPbX3@SiO2 quantum dots using cesium acetate instead of cesium carbonate. The results showed that CsPbX3@SiO2 presents good crystallinity and excellent luminescence properties. The coating layer of SiO2 on the CsPbX3 quantum dots surface blocks the air and water contact and suppresses anion exchange between the quantum dots, which dramatically enhances the stability. White light-emitting diode devices are manufactured by integrating the green CsPbBr3@SiO2 quantum dots and red CsPbBr1 I2@SiO2 quantum dots on the blue GaN chips. The devices show stable white light emission with Commission Internationale de L'Eclairage color coordinates (0.3511, 0.3437), and the white light intensity keeps unchanged after continuously working for 16 hours. The results indicate that CsPbX3@SiO2 quantum dots can be an ideal down-conversion fluorescent material for white light-emitting diode devices.

scholarly journals Multiple Energy Transfer in Luminescence-Tunable Single-Phased Phosphor NaGdTiO4: Tm3+, Dy3+, Sm3+

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1249 ◽  
Author(s):  
Jun Xiao ◽  
Cong Wang ◽  
Xin Min ◽  
Xiaowen Wu ◽  
Yangai Liu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Solid State ◽  
White Light ◽  
Single Phase ◽  
Light Emission ◽  
Photoluminescence Properties ◽  
Light Emitting ◽  
Energy Transfers ◽  
White Light Emitting Diodes ◽  
Tunable Emission

Advances in solid-state white-light-emitting diodes (WLEDs) necessitate the urgent development of highly efficient single-phase phosphors with tunable photoluminescence properties. Herein, the Tm3+, Dy3+, and Sm3+ ions are incorporated into the orthorhombic NaGdTiO4 (NGT) phosphors, resulting in phosphors that fulfill the aforementioned requirement. The emission spectrum of Tm3+ ions overlaps well with the adsorption spectra of both Dy3+ and Sm3+ ions. Under the excitation at 358 nm, the single-phase NaGdTiO4: Tm3+, Dy3+, Sm3+ phosphor exhibits tunable emission peaks in the blue, yellow, and red regions simultaneously, resulting in an intense white-light emission. The coexisting energy transfer behaviors from Tm3+ to Dy3+ and Sm3+ ions and the energy transfer from Dy3+ to Sm3+ ions are demonstrated to be responsible for this phenomenon. The phosphors with multiple energy transfers enable the development of single-phase white-light-emitting phosphors for phosphor-converted WLEDs.

scholarly journals White-Light Emitting Di-Ureasil Hybrids

Materials ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 2246 ◽  
Author(s):  
Ming Fang ◽  
Lianshe Fu ◽  
Rute Ferreira ◽  
Luís Carlos
Keyword(s):  
White Light ◽  
Light Emission ◽  
Relative Concentration ◽  
Sol Gel ◽  
Quantum Yields ◽  
Excitation Wavelength ◽  
Light Sources ◽  
Efficient Energy Transfer ◽  
Visible Absorption ◽  
Light Emitting

White-light emitting materials have emerged as important components for solid state lighting devices with high potential for the replacement of conventional light sources. Herein, amine-functionalized organic-inorganic di-ureasil hybrids consisting of a siliceous skeleton and oligopolyether chains codoped with lanthanide-based complexes, with Eu3+ and Tb3+ ions and 4,4′-oxybis(benzoic acid) and 1,10-phenanthroline ligands, and the coumarin 1 dye were synthesized by in situ sol–gel method. The resulting luminescent di-ureasils show red, green, and blue colors originated from the Eu3+, Tb3+, and C1 emissions, respectively. The emission colors can be modulated either by variation of the relative concentration between the emitting centers or by changing the excitation wavelength. White light emission is achieved under UV excitation with absolute quantum yields of 0.148 ± 0.015, 0.167 ± 0.017, and 0.202 ± 0.020 at 350, 332, and 305 nm excitation, respectively. The emission mechanism was investigated by photoluminescence and UV–visible absorption spectroscopy, revealing an efficient energy transfer from the organic ligands to the Ln3+ ions and the organic dye, whereas negligible interaction between the dopants is discerned. The obtained luminescent di-ureasils have potential for optoelectronic applications, such as in white-light emitting diodes.

Sign in / Sign up

Export Citation Format

Share Document