Yellow Emission Obtained by Combination of Broadband Emission and Multi-Peak Emission in Garnet Structure Na2YMg2V3O12: Dy3+ Phosphor

The fabrication and luminescent performance of novel phosphors Na2YMg2V3O12:Dy3+ were investigated by a conventional solid-state reaction method. Under near-UV light, the Na2YMg2V3O12 host self-activated and released a broad emission band (400–700 nm, with a peak at 524 nm) ascribable to charge transfer in the (VO4)3− groups. Meanwhile, the Na2YMg2V3O12:Dy3+ phosphors emitted bright yellow light within both the broad emission band of the (VO4)3- groups and the sharp peaks of the Dy3+ ions at 490, 582, and 663 nm at a quenching concentration of 0.03 mol. The emission of the as-prepared Na2YMg2V3O12:Dy3+ phosphors remained stable at high temperatures. The obtained phosphors, commercial Y2O3:Eu3+ red phosphors, and BaMgAl10O17:Eu2+ blue phosphors were packed into a white light-emitting diode (WLED) device with a near-UV chip. The designed WLED emitted bright white light with good chromaticity coordinates (0.331, 0.361), satisfactory color rendering index (80.2), and proper correlation to a color temperature (7364 K). These results indicate the potential utility of Na2YMg2V3O12:Dy3+ phosphor as a yellow-emitting phosphor in solid-state illumination.

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Synthesis and Photoluminescence Properties of Eu3+-Doped Na2YMg2V3O12: A Novel Red-Emitting Phosphor for White-Light-Emitting Diodes

10.21203/rs.3.rs-736843/v1 ◽

2021 ◽

Author(s):

Weiyi Zhang ◽

Yanqiu Shao ◽

Ying Zhu ◽

Yingying Shao ◽

Zhaohui Huang ◽

...

Keyword(s):

Solid State ◽

White Light ◽

Emission Band ◽

Red Light ◽

Solid State Reactions ◽

Broad Emission Band ◽

Light Emitting ◽

Near Ultraviolet ◽

Broad Emission ◽

Red Emitting Phosphor

Abstract The fabrication and luminescent properties of novel Na2YMg2V3O12:Eu3+ phosphors produced by conventional solid-state reactions were investigated. Self-activated emission of the Na2YMg2V3O12 host produces a broad emission band ranging from 400 to 700 nm with a maximum peak at 530 nm, ascribed to the charge transfer in the (VO4)3− groups. Excitation with near-UV (365 nm) light causes the Na2YMg2V3O12:Eu3+ phosphors to emit bright red light, including both the broad emission band of the (VO4)3− groups and the sharp emission peaks of Eu3+ ions. At a quenching concentration of 0.03 mol, the Eu3+ ion emission peaks were located at 597, 613, 654 and 710 nm. As-prepared Na2YMg2V3O12:Eu3+ phosphors also exhibited stable emission at high temperatures. Furthermore, a designed and packaged white-light-emitting diode (WLED) lamp, including the obtained phosphors, commercial (Ba,Sr)2SiO4:Eu2+ green phosphors, BaMgAl10O17:Eu2+ blue phosphors and a near-ultraviolet (n-UV) chip, emitted bright white light with a good chromaticity coordinate of (0.3068, 0.3491), a satisfactory colour rendering index of 88.20 and a properly correlated colour temperature of 4460.52 K. These results indicate the potential of this Na2YMg2V3O12:Eu3+ phosphor as a red-emitting phosphor for solid-state illumination.

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Optical and structural properties of curcuminoids extracted from Curcuma longa L. for hybrid white light diode

The European Physical Journal Applied Physics ◽

10.1051/epjap/2018180185 ◽

2018 ◽

Vol 84 (1) ◽

pp. 10501 ◽

Cited By ~ 2

Author(s):

M. Al Shafouri ◽

Naser M. Ahmed ◽

Z. Hassan ◽

Munirah Abdullah Almessiere ◽

Maadh Jumaah

Keyword(s):

White Light ◽

Dye Degradation ◽

Uv Light ◽

Light Emitting Diode ◽

Curcuma Longa ◽

Stress Test ◽

Air Gap ◽

Color Temperature ◽

Soxhlet Apparatus ◽

Normal Method

In this study, curcuminoids were extracted from turmeric (Curcuma longa L.) by means of three methods, comprising the normal method, use of Soxhlet apparatus and by combining the normal method with the Soxhlet extraction approach. The limitation of stickiness in the use of curcuminoids was resolved by mixing it with silica gel. The curcuminoids used light down-conversion of UV light (390 nm) for the white light-emitting diode (WLED). The characteristics of the white light chromaticity were controlled by changing the current and concentration of the curcuminoids. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for different applied currents (20, 60 and 100 mA) and weights (25, 35 and 50 mg) of curcuminoids. It was observed from the concentration of phosphor that the combination of the normal and Soxhlet apparatus methods is most effective extraction approach. The results showed that increasing the concentration of phosphor significantly and remarkably increased the value of CCT when different values of current were applied. The stress test showed that the prolongation of dye degradation can be improved using air gap and glass slid, with air gap being more effective. An optimum color rendering index (CRI) value of 61.2 is obtained. The white phosphor exhibited CIE values of 0.333, 0.3151 and color temperature (CCT) of 5405 K.

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Chromaticity Study of Curcumin Dye Extracted from Curcuma longa L. Using for UV Light down Conversion for White Light Emitting Diode

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.290.183 ◽

2019 ◽

Vol 290 ◽

pp. 183-189

Author(s):

Mahmood Al Shafouri ◽

Naser Mahmoud Ahmed ◽

Zainuriah Hassan ◽

Munirah Abdullah Almessiere

Keyword(s):

White Light ◽

Uv Light ◽

Light Emitting Diode ◽

Curcuma Longa ◽

Color Temperature ◽

Light Emitting ◽

Chromaticity Coordinates ◽

Major Factors ◽

Color Rendering ◽

Down Conversion

In thus study, Turmeric phosphor dye was extracted from Curcuma Longa L. via a simple technique using silica gel. The phosphor was used for light down-conversion of UV light for the manufacture white light emitting diode (WLED). The UV-LED was analyzed over 395nm wavelengths. The characteristics of the white light chromaticity were controlled by tuning the current and phosphor concentration. An optimum color rendering index (CRI) value of 63.4 was obtained. The chromaticity coordinates (CIE) and correlated color temperature (CCT) were measured for various currents and phosphor concentrations. The white phosphor exhibited CIE value of 0.355,0.338 and CCT of 4567 K. The concentration of phosphor and amount of applied current were confirmed to be major factors that control the intensity of white light emitted from the sample, where CIE and CRI of the emitted light steadily increased with the concentration of phosphor and current. Thus, phosphor concentration has a critical effect on conversion efficiency. Key words: Turmeric, phosphor, WLED, curcumin

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Luminescence Property of Eu2+ Doped Strontium Silicate Yellow Phosphor for White Light Emitting Diode

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.363 ◽

2008 ◽

Vol 368-372 ◽

pp. 363-365

Author(s):

Hong He ◽

Ren Li Fu ◽

Xiu Feng Song ◽

De Liu Wang

Keyword(s):

White Light ◽

Luminescence Property ◽

Light Emitting Diode ◽

Broad Emission Band ◽

Conventional Solid State Reaction ◽

Weak Band ◽

Yellow Colour ◽

Light Emitting ◽

Yellow Phosphor ◽

Strontium Silicate

Eu2+ activated strontium silicate (Sr3SiO5:Eu2+) yellow phosphor was prepared by the conventional solid-state reaction technique in reduction atmosphere with starting materials SrCO3, SiO2 and Eu2O3. The phase, morphology and luminescence property of the samples were analyzed. The X-ray diffraction analysis showed the main phase in all samples is tetragonal Sr3SiO5. With Eu2+ ions doped into the host lattice, the Sr3SiO5:Eu2+ phosphors absorb light energy in the UV-visible spectrum region and show an intense broad emission band in the yellow colour range (around 570 nm) and a weak band in the blue region (around 470 nm). The excitation and the emission bands are originated from the 4f−5d transition of Eu2+ ions. When the concentration of Eu2+ ions increases, the emission peaks of phosphors shift to longer wavelengths. The effective emission in the yellow colour indicates that phosphor as potential candidates for white light-emitting-diodes.

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Phosphor-Conversion White Light Emitting Diode Using InGaN Near-Ultraviolet Chip

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.124-126.499 ◽

2007 ◽

Vol 124-126 ◽

pp. 499-502 ◽

Cited By ~ 3

Author(s):

Kyoung Jae Choi ◽

Joung Kyu Park ◽

Kyung Nam Kim ◽

Chang Hae Kim ◽

Ho Kun Kim

Keyword(s):

White Light ◽

Uv Light ◽

Light Emitting Diode ◽

Forward Bias ◽

Color Temperature ◽

Operating Voltage ◽

Current Increase ◽

Light Emitting ◽

Near Ultraviolet ◽

Yellow Region

We have synthesized a Eu2+-activated Sr3MgSi2O8 blue phosphor and (Sr,Ba)2SiO4 yellow phosphor. We fabricated a phosphor-conversion white light emitting diode(LED) using an InGaN chip that emits 400 nm near-ultraviolet(n-UV) light and phosphors that emit in the blue and yellow region. When the white LED was operated at a forward-bias current of 20 mA at room temperature(RT), the color temperature(Tcp), average color rendering(Ra), operating voltage(Vf) and luminous efficacy(ηL) were estimated to be 5800K, 72.08, 3.4V, and 7.61 lm/W, respectively. The commission International de I’Eclarirage(CIE) chromaticity coordinates obtained from the measured spectra remained almost constant during the forward-baias current increase from 0.5 mA to 60 mA.

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A New Salt-Inclusion Single-Phased White Phosphor Ba7B3SiO13Br:Dy3+ for White Light-Emitting Diodes

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.803.93 ◽

2019 ◽

Vol 803 ◽

pp. 93-97

Author(s):

Hai Dong Ju ◽

Bao Ling Wang ◽

Qi Mei Yang

Keyword(s):

White Light ◽

Emission Band ◽

Light Emitting Diodes ◽

Hexagonal Phase ◽

Blue Emission ◽

Yellow Emission ◽

Conventional Solid State Reaction ◽

Blue Emission Band ◽

Light Emitting ◽

White Light Emitting Diodes

A series of Ba7B3SiO13Br:Dy3+ phosphors were synthesized by a conventional solid-state reaction method for the first time. The X-ray diffraction patterns confirmed that the samples were pure phase and crystallized in a hexagonal phase with a space group of the P63mc (186). The luminescence spectrum exhibited a strong blue emission band peaked at 478 nm, a strong yellow emission band at 575 nm and a weak emission band at 665 nm, corresponding to the transitions from 4F9/2 to 6H15/2, 6H13/2 and 6H13/2 of Dy3+, respectively. According to the emission spectrum of Ba6.92B3SiO13Br:0.08Dy3+ excited at 349 nm, the chromaticity coordinate was calculated to be (0.317, 0.358) located on the white light region. The concentration quenching mechanism of Dy3+ in Ba7B3SiO13Br was ascribed to the multipolar-multipolar interaction. The current researches suggested that the phosphor can be used as a white phosphor suitable for white light-emitting diodes.

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Li2SrSiO4:Eu2+ phosphor prepared by the Pechini method and its application in white light emitting diode

Journal of Materials Research ◽

10.1557/jmr.2008.0394 ◽

2008 ◽

Vol 23 (12) ◽

pp. 3288-3294 ◽

Cited By ~ 43

Author(s):

Hong He ◽

Renli Fu ◽

Hai Wang ◽

Xiufeng Song ◽

Zhengwei Pan ◽

...

Keyword(s):

Solid State ◽

White Light ◽

Solid State Reaction ◽

Light Emitting Diode ◽

Pechini Method ◽

Sol Gel ◽

Color Temperature ◽

Light Emitting ◽

White Leds ◽

Luminescence Efficiency

Eu2+-doped Li2SrSiO4 phosphors were prepared by two different synthesis processes, the Pechini sol-gel route and solid-state reaction (SSR) method. Their morphology, crystal structure, and luminescence properties have been characterized. Li2SrSiO4:Eu2+ phosphors show broad and intensive excitation in the range of 390–480 nm and emit yellow-orange light extending from 500 to 700 nm. The luminescence efficiency of Li2SrSiO4: Eu2+ phosphors synthesized through the Pechini route is much better than that of phosphors prepared by solid-state reaction method. The application of phosphors from the Pechini route in white light emitting diodes (LEDs) has been investigated. The Commission Internationale de L’Eclairage (CIE) chromaticity coordinates and the correlated color temperature of these white LEDs have been calculated; they are comparable to corresponding values of commercial Y3Al5O12:Ce3+ converted white LEDs.

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Near Unity PLQY and High Stability of Barium Thiocyanate Based All-Inorganic Perovskites and Their Applications in White Light-Emitting Diodes

Photonics ◽

10.3390/photonics8060209 ◽

2021 ◽

Vol 8 (6) ◽

pp. 209

Author(s):

Gopi Chandra Adhikari ◽

Saroj Thapa ◽

Yang Yue ◽

Hongyang Zhu ◽

Peifen Zhu

Keyword(s):

White Light ◽

Large Scale ◽

Light Emitting Diode ◽

Photophysical Properties ◽

Environmental Stability ◽

Color Temperature ◽

Ambient Atmosphere ◽

Light Emitting ◽

Halide Perovskite ◽

Lead Halide

All-inorganic lead halide perovskite (CsPbX3) nanocrystals (NCs) have emerged as a highly promising new generation of light emitters due to their extraordinary photophysical properties. However, the performance of these semiconducting NCs is undermined due to the inherent toxicity of lead and long-term environmental stability. Here, we report the addition of B-site cation and X-site anion (pseudo-halide) concurrently using Ba(SCN)2 (≤50%) in CsPbX3 NCs to reduce the lead and improve the photophysical properties and stability. The as-grown particles demonstrated an analogous structure with an almost identical lattice constant and a fluctuation of particle size without altering the morphology of particles. Photoluminescence quantum yield is enhanced up to near unity (~98%) by taking advantage of concomitant doping at the B- and X-site of the structure. Benefitted from the defect reductions and stronger bonding interaction between Pb2+ and SCN− ions, Ba(SCN)2-based NCs exhibit improved stability towards air and moisture compared to the host NCs. The doped NCs retain higher PLQY (as high as seven times) compared to the host NCs) when stored in an ambient atmosphere for more than 176 days. A novel 3D-printed multiplex color conversion layer was used to fabricate a white light-emitting diode (LED). The obtained white light shows a correlated color temperature of 6764 K, a color rendering index of 87, and luminous efficacy of radiation of 333 lm/W. In summary, this work proposes a facile route to treat sensitive lead halide perovskite NCs and to fabricate LEDs by using a low-cost large-scale 3-D printing method, which would serve as a foundation for fabricating high-quality optoelectronic devices for near future lighting technologies.

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