scholarly journals Luminescence and energy transfer of warm white-emitting phosphor Mg2Y2Al2Si2O12:Dy3+,Eu3+ for white LEDs

RSC Advances ◽  
2021 ◽  
Vol 11 (52) ◽  
pp. 32707-32716
Author(s):  
Zizhong Zhu ◽  
Chunjing Tao ◽  
Zhijun Wang ◽  
Zhiping Yang ◽  
Panlai Li
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Color Temperature ◽  
White Leds ◽  
Warm White Light ◽  
Chromaticity Coordinates ◽  
Cie Chromaticity

MYAS:xDy3+,yEu3+ can produce warm white light with CIE chromaticity coordinates of (0.4071, 0.3944) and relative color temperature of 3500 K.

scholarly journals Lead Borate Glasses and Glass-Ceramics Singly Doped with Dy3+ for White LEDs

Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5022
Author(s):  
Agata Górny ◽  
Marta Kuwik ◽  
Wojciech A. Pisarski ◽  
Joanna Pisarska
Keyword(s):  
White Light ◽  
Glass Ceramics ◽  
Borate Glasses ◽  
Spectroscopic Techniques ◽  
Lead Borate ◽  
White Leds ◽  
Lead Borate Glasses ◽  
Chromaticity Coordinates ◽  
Potential Applications ◽  
Cie Chromaticity

In this paper, some series of lead borate glasses and glass ceramics singly doped with Dy3+ ions were prepared and then studied using spectroscopic techniques. Our research includes mainly studies of the luminescence properties of received materials for white light. The luminescence bands associated with the characteristic 4F9/2→6H15/2 (blue), 4F9/2→6H13/2 (yellow) and 4F9/2→6H11/2 (red) transitions of trivalent dysprosium in lead borate systems are well observed. In particular, the Commission Internationale de I’Eclairage (CIE) chromaticity coordinates (x, y) were calculated in relation to potential applications for white light-emitting diodes (W-LEDs). Their values depend on the relative B2O3/PbO ratios and PbX2 contents (where X = Cl, F, Br) in glass composition. For glass-ceramics, the chromaticity coordinates are changed significantly under different excitation wavelengths.

scholarly journals Preparation of Bismuth Oxide Photocatalyst and Its Application in White-light LEDs

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yen-Chang Chu ◽  
Gang-Juan Lee ◽  
Chin-Yi Chen ◽  
Shih-Hsin Ma ◽  
Jerry J. Wu ◽  
...  
Keyword(s):  
Bismuth Oxide ◽  
White Light ◽  
Front Surface ◽  
Color Temperature ◽  
Spray Pyrolysis Method ◽  
Light Emitting ◽  
White Leds ◽  
Air Purifier ◽  
Cie Chromaticity ◽  
White Light Emitting Diodes

Bismuth oxide photocatalysts were synthesized and coated on the front surface of phosphor-converted white light-emitting diodes to produce a safe and environmentally benign lighting source. Bismuth oxide photocatalyst powders were synthesized with a spray pyrolysis method at 500°C, 600°C, 700°C, and 800°C. Using the absorption spectrum in the blue and UV regions of the bismuth oxide photocatalysts, the blue light and UV leakage problems of phosphor-converted white LEDs can be significantly reduced. The experimental results showed that bismuth oxide photocatalyst synthesized at 700°C exhibited the most superior spectrum inhibiting ability. The suppressed ratio reached 52.33% in the blue and UV regions from 360 to 420 nm. Related colorimetric parameters and the photocatalyst decomposition ability of fabricated white-light LEDs were tested. The CIE chromaticity coordinates(x,y)were (0.349, 0.393), and the correlated color temperature was 4991 K. In addition, the coating layer of photocatalyst can act as an air purifier and diffuser to reduce glare. A value of66.2±0.60 ppmv of molecular formaldehyde gas can be decomposed in 120 mins.

High color rendering index single phase white light emitting phosphors based on Tb3+/Sm3+ co-doped CePO4 nanocrystals: the role of Tb3+ as a bridge between Ce3+ and Sm3+

2019 ◽  
Vol 43 (44) ◽  
pp. 17367-17382 ◽  
Author(s):  
Sisira S. ◽  
Linju Ann Jacob ◽  
Kamal P. Mani ◽  
Biju P. R. ◽  
N. V. Unnikrishnan ◽  
...  
Keyword(s):  
White Light ◽  
Single Phase ◽  
Color Temperature ◽  
Light Emitting ◽  
Chromaticity Coordinates ◽  
Color Rendering Index ◽  
Cie Chromaticity ◽  
Color Rendering

Single phase white light emitting CePO4 nanocrystals doped with Tb3+ and Sm3+ were synthesized. The quality of white light is characterized by CIE chromaticity coordinates, color temperature, color rendering index and quantum yield.

Color-tunable Al6Si2O13:Eu2+,Mn2+ phosphor with high color rendering index based on energy transfer for warm white LEDs

2018 ◽  
Vol 42 (18) ◽  
pp. 15207-15214 ◽  
Author(s):  
Bo Yan ◽  
Gui-Gen Wang ◽  
Long-Fei Liu ◽  
Xin-Zhong Wang ◽  
You-Xiao Chen ◽  
...  
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
White Led ◽  
Light Emitting ◽  
White Leds ◽  
Warm White Light ◽  
Color Tunable ◽  
Color Rendering Index ◽  
Color Rendering

A type of warm-white-light-emitting Al6Si2O13:Eu2+,Mn2+ phosphor with high color rendering index was synthesized for UV-excited white LED.

A novel single-phase warm white emission phosphor Sr3YAl2O7.5:Bi3+,Eu3+ with energy transfer for UV white LEDs

RSC Advances ◽  
2016 ◽  
Vol 6 (48) ◽  
pp. 42618-42626 ◽  
Author(s):  
Yichao Wang ◽  
Jianyan Ding ◽  
Yanyan Li ◽  
Linfen Yang ◽  
Xin Ding ◽  
...  
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Single Phase ◽  
Light Emitting ◽  
White Leds ◽  
White Emission ◽  
Warm White Light ◽  
Color Tunable

A series of color-tunable warm white-light emitting phosphors Sr3YAl2O7.5:xBi3+, yEu3+.

Correlated color temperature tunability and energy transfer phenomenon in the NaBaBO3:Dy3+/Eu3+ phosphor for white light application

2015 ◽  
Vol 08 (06) ◽  
pp. 1550077 ◽  
Author(s):  
Jianghui Zheng ◽  
Qijin Cheng ◽  
Cheng Zheng ◽  
Guo Chen ◽  
Feng Shi ◽  
...  
Keyword(s):  
Energy Transfer ◽  
White Light ◽  
Single Phase ◽  
Color Temperature ◽  
Light Emitting ◽  
Transfer Phenomenon ◽  
Near Ultraviolet ◽  
Cie Chromaticity ◽  
Co Doped ◽  
The Eu

NaBa 0.97-x BO 3 0.03 Dy 3+, x Eu 3+(0 ≤ x ≤ 0.09) single-phase white phosphors with tunable correlated color temperature (CCT) were synthesized using a conventional solid state reaction method. The phase structure and luminescence properties of the as-prepared samples were investigated. The Dy 3+, Eu 3+ doped and Dy 3+/ Eu 3+ co-doped NaBaBO 3 phosphors excited by 361 nm show two blue and yellow emissions corresponding to the 4 F 9/2 → 6 H 15/2 and 4 F 9/2 → 6 H 13/2 transitions of Dy 3+ ions and two red emissions due to the 5 D 0 → 4 F J (J = 1, 2) transitions of Eu 3+ ions. Under 361-nm light excitation, the NaBa 0.97-x BO 3 0.03 Dy 3+, x Eu 3+(0 ≤ x ≤ 0.09) phosphors feature a white light emitting property. Through the Commission Internationale de L'Eclairage (CIE) chromaticity analysis and CCT calculation, the CIE chromaticity coordinates of the emission light are all located in the white region and can be tuned from bluish white light to reddish white light when the Eu 3+ concentration increases, and the CCT values of the obtained samples can vary from 5514.31 K to 8269.42 K. Furthermore, the energy transfer phenomenon from Dy 3+ ions to Eu 3+ ions in Dy 3+/ Eu 3+ co-doped samples was also investigated. The results indicated that, through tuning the Eu 3+ concentration of the NaBaBO 3: Dy 3+/ Eu 3+ phosphors, the NaBaBO 3-based phosphor can act as a potential single-phase white emitting phosphor for the application in the near-ultraviolet (NUV) white light emitting diodes.

Effects of Sintering Route and Flux on the Luminescence and Morphology of YAG: Ce Phosphors for White Emitting-Light Diodes (LEDs)

2012 ◽  
Vol 236-237 ◽  
pp. 9-15
Author(s):  
Tao Han ◽  
Shi Xiu Cao ◽  
Ming Xing Ma ◽  
Da Chuan Zhu ◽  
Cong Zhao ◽  
...  
Keyword(s):  
White Light ◽  
Potential Application ◽  
Color Temperature ◽  
Precipitation Method ◽  
Photoluminescence Intensity ◽  
White Led ◽  
White Leds ◽  
Chromaticity Coordinates ◽  
Co Precipitation ◽  
Surface Morphologies

YAG:Ce phosphors were synthesized by co-precipitation method. The photoluminescence intensity of samples sintered by the two-step route increases by about 10%, and with 0.5 wt.% NH4Cl added as flux, surface morphologies and size distribution are improved. The white LEDs were fabricated using as-obtained phosphors. It shows natural white light with chromaticity coordinates of (0.3083, 0.3163), color temperature (Tc) of 6886 K, the average CRI of 75, and the luminous efficacy of 85 ml/W. Therefore, The as-obtained YAG:Ce phosphors could be regard to have potential application in white LED devices.

scholarly journals A Novel Polymethyl Methacrylate Derivative Grafted with Cationic Iridium(III) Complex Units: Synthesis and Application in White Light-Emitting Diodes

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 499 ◽  
Author(s):  
Huaijun Tang ◽  
Xueyan Dong ◽  
Mingxian Chen ◽  
Qiuhong Chen ◽  
Mengran Ren ◽  
...  
Keyword(s):  
Polymethyl Methacrylate ◽  
White Light ◽  
Light Emitting Diodes ◽  
Thermal Quenching ◽  
Decomposition Temperature ◽  
Color Temperature ◽  
Light Emitting ◽  
White Leds ◽  
Orange Yellow ◽  
Cie Chromaticity

A novel orange-yellow-emitting polymethyl methacrylate derivative grafted with cationic iridium(III) complex units was synthesized and used as down-conversion luminescent materials in light-emitting diodes (LEDs). The polymer had a thermal decomposition temperature (Td) of 275 °C. With the temperature increasing from 20 to 100 °C, its photoluminescent intensity decreased to 76.8% with thermal quenching activation energy (Ea) of 0.2775 eV. A series of LEDs was fabricated by 460 nm blue GaN chips and the polymer blended in silicone at different concentrations. At 4.0 wt %, a cold white LED was obtained, the correlated color temperature (CCT) was 10,050 K, color rendering index (CRI) was 71.2, luminous efficiency (ηL) was 5.3 lm·w−1, and Commission Internationale de L’Eclairage (CIE) chromaticity coordinates were (0.30, 0.24). At 5.0 wt.%, the LED emitted neutral white light, its CCT was 4938 K, CRI was 75, ηL was 13.8 lm·w−1, and the CIE value was (0.34, 0.27). At 5.5 wt %, 6.0 wt %, 7.0 wt %, and 8.0 wt %, the LEDs all emitted warm white light; their CCTs were 3446, 3093, 2557, and 2337 K, respectively; their CRIs were 73.6, 71.8, 63.8, and 59.0, respectively; their ηL were 18.1, 16.3, 14.8, and 13.7 lm·w−1, respectively; and their CIE values were (0.36, 0.30), (0.40, 0.35), (0.45, 0.38), and (0.50, 0.42), respectively. At 9.0 wt %, the blue light of GaN chip was completely absorbed by the polymer and only the orange-yellow light of the polymer emitted. The results suggested the polymer was a promising orange-yellow-emitting phosphor candidate for white LEDs, especially for warm white LEDs.

scholarly journals Effective Red Compensation ofSr2SiO4 : Dy3+Phosphor by CodopingMn2+Ions and Its Energy Transfer

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Le Zhang ◽  
Zhou Lu ◽  
Pengde Han ◽  
Lixi Wang ◽  
Qitu Zhang
Keyword(s):  
Energy Transfer ◽  
Energy Transfer Process ◽  
Solid State Reaction Method ◽  
Photoluminescence Properties ◽  
Red Emission ◽  
White Leds ◽  
Chromaticity Coordinates ◽  
Single Matrix ◽  
Cie Chromaticity ◽  
Electric Multipoles

Mn2+ions codoped Sr2SiO4 : Dy3+phosphors were prepared by the solid-state reaction method using NH4Cl as the flux. Their phase compositions, photoluminescence properties, and the energy transfer process were systematically investigated. All Mn/Dy codoped powders wereα′-Sr2SiO4. The codoping concentration range of Mn2+was≤4.0 mol% to keep the structure undamaged. The broad red emission of Mn2+centered at 647 nm in Sr2SiO4 : Mn, Dy powders, which effectively compensated the red emission of Sr2SiO4 : Dy3+phosphor. The CIE chromaticity coordinates dramatically changed from (0.310, 0.340) to (0.332, 0.326) due to the red enhancement via the energy transfer from Dy3+to Mn2+. This energy transfer is realized by the exchange interaction. But the luminescence quenching of Sr2SiO4 : Dy, Mn phosphor was mainly caused by the electric multipoles interaction. The concentration optimized (Sr0.96, Mn0.02, Dy0.02)2SiO4phosphor with high and almost pure white emission has great potential to act as a single-matrix white phosphor for white LEDs.

A direct warm-white-light CaLa2(MoO4)4: Tb3+, Sm3+ phosphor with tunable color tone via energy transfer for white LEDs

RSC Advances ◽  
2015 ◽  
Vol 5 (95) ◽  
pp. 77866-77872 ◽  
Author(s):  
Wei Xie ◽  
Guixia Liu ◽  
Xiangting Dong ◽  
Jinxian Wang ◽  
Wensheng Yu
Keyword(s):  
Energy Transfer ◽  
Ultraviolet Radiation ◽  
White Light ◽  
Solvothermal Method ◽  
Color Tone ◽  
White Leds ◽  
Warm White Light ◽  
Co Doped

Tb3+ and Sm3+ co-doped CaLa2(MoO4)4 phosphors were prepared by a solvothermal method. Under different ultraviolet radiation, warm-white-light emissions are realized, and the phosphors could be favorable candidates for white LEDs.

Sign in / Sign up

Export Citation Format

Share Document