The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
Fengwen Kang - One of the best experts on this subject based on the ideXlab platform.
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a red emitting heavy Doped Phosphor li6y bo3 3 eu3 for white light emitting diodes
Optical Materials, 2011Co-Authors: Guifang Ju, Yihua Hu, Haoyi Wu, Zhongfu Yang, Chujun Fu, Zhongfei Mu, Fengwen KangAbstract:A series of Eu3+ activated Li6Y1−xEux(BO3)3 (0.05 ⩽ x ⩽ 1) Phosphors were synthesized by solid-state reaction method. The structures and photoluminescent properties of the Phosphors were investigated at room temperature. The results of XRD patterns indicate that these Phosphors are isotypic to the monoclinic Li6Gd(BO3)3. The excitation spectra indicate that these Phosphors can be effectively excited by near UV (370–410 nm) light. The red emission from transition 5D0→7F2 is dominant. The emission spectra exhibit strong red performance (CIE chromaticity coordinates: x = 0.65, y = 0.35), which is due to the 5D0−7FJ transitions of Eu3+ ions. The relationship between the structure and the photoluminescent properties of the Phosphors was studied. The concentration quenching occurs at x ≈ 0.85 under near UV excitation. Li6Y(BO3)3:Eu3+ has potential application as a Phosphor for white light-emitting diodes.
Vikas Dubey - One of the best experts on this subject based on the ideXlab platform.
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Near UV-Blue Emission From Cerium Doped Zirconium Dioxide Phosphor for Display and Sensing Applications
Journal of Display Technology, 2016Co-Authors: Neha Tiwari, Vikas Dubey, Jaideep Dewangan, Nitin JainAbstract:Near UV-blue emission from cerium ion percentage of ZrO2 Phosphor was reported in the manuscript. The samples were prepared by combustion synthesis technique which is suitable for less time taking techniques. Starting material for sample preparation are Zr(NO3)3 and Ce(NO3)3 and urea used as a fuel. Here the variable percentage of cerium ion was (0.1 to 2.5 mol%) used. The prepared sample was characterized by X-ray diffraction analysis for structural analysis and it is found the cubic structure also crystallite size were calculated by Scherer's formula. Morphology and particle size of prepared sample for optimized concentration of cerium was analyzed by field emission gun scanning electron microscopy and high resolution transmission electron microscopy technique. All prepared Phosphor with variable concentration of Ce3+ (0.1 to 2.5 mol%) was studied by photoluminescence analysis and it is found that the excitation spectra of prepared Phosphor shows broad excitation centred at 396 nm (near UV-blue region). The emission spectra with variable concentration of Ce3+ show strong peaks at 447 nm (blue region). Spectrophotometric determinations of peaks are evaluated by Commission Internationale de I'Eclairage (CIE) technique. Using this Phosphor, the desired CIE values including emissions throughout the violet (396 nm) and intense blue (427 nm) of the spectra were achieved. Efficient blue light emitting diodes (LEDs) were fabricated using Ce3+ Doped Phosphor based on near ultraviolet excited LED lights. Also the prepared Phosphor was useful for sensing application such as biological and chemical sensing.
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White Light Emission by Dy^3+ Doped Phosphor Matrices: A Short Review
Journal of Fluorescence, 2016Co-Authors: Ravi Shrivastava, Jagjeet Kaur, Vikas DubeyAbstract:In this review we have studied number of research papers related to white light emission from Dy^3+ Doped different host matrices. It is observed that most of the Dy^3+Doped aluminates, silicates, borates etc., emitted blue, green and red colour with specific intensities so that CIE coordinates, appeared near to white light. Correlated Colour Temperature (CCT) values of these Phosphors expressed that the white light emission produced, was adaptable to human eyes. Dy^3+ ions act as activator in each case. Four peaks at approximately 480, 575, 670, and 757 nm could be seen in most of the Dy^3+ Doped Phosphors. Expected transition responsible for these peaks are ^4F_9/2 → ^6H_15/2 (Blue Colour), ^4F_9/2 → ^6H_13/2 (Green-Yellow Colour), ^4F_9/2 → ^6H_11/2 (Red Colour) and ^4F_9/2 → ^6H_9/2 (Brownish Red Colour). Few of the discussed Phosphors exhibited long Phosphorescence, starting from several minutes to few hours. Mechanism responsible for long lasting white light emission was also discussed. Five different factors, to recognize the Phosphors for its suitability as commercial white light Phosphor have been discussed.
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White Light Emission by Dy3+ Doped Phosphor Matrices: A Short Review.
Journal of Fluorescence, 2015Co-Authors: Ravi Shrivastava, Jagjeet Kaur, Vikas DubeyAbstract:In this review we have studied number of research papers related to white light emission from Dy3+ Doped different host matrices. It is observed that most of the Dy3+Doped aluminates, silicates, borates etc., emitted blue, green and red colour with specific intensities so that CIE coordinates, appeared near to white light. Correlated Colour Temperature (CCT) values of these Phosphors expressed that the white light emission produced, was adaptable to human eyes. Dy3+ ions act as activator in each case. Four peaks at approximately 480, 575, 670, and 757 nm could be seen in most of the Dy3+ Doped Phosphors. Expected transition responsible for these peaks are 4F9/2 → 6H15/2 (Blue Colour), 4F9/2 → 6H13/2 (Green-Yellow Colour), 4F9/2 → 6H11/2 (Red Colour) and 4F9/2 → 6H9/2 (Brownish Red Colour). Few of the discussed Phosphors exhibited long Phosphorescence, starting from several minutes to few hours. Mechanism responsible for long lasting white light emission was also discussed. Five different factors, to recognize the Phosphors for its suitability as commercial white light Phosphor have been discussed.
J J Velazquezsalazar - One of the best experts on this subject based on the ideXlab platform.
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strong blue and white photoluminescence emission of bazro3 unDoped and lanthanide Doped Phosphor for light emitting diodes application
ChemInform, 2013Co-Authors: V H Romero, E De La Rosa, Pedro Salas, J J VelazquezsalazarAbstract:Perovskite BaZrO3:Tm3+ submicron crystals are prepared from aqueous mixtures of Ba(NO3)2 and ZrCl2 as host precursors, TmCl3 as dopant, cetyl trimethylammonium bromide, EtOH, and NaOH (autoclave, 100 °C, 24 h; annealing in air at 1000 °C, 3 h).
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strong blue and white photoluminescence emission of bazro3 unDoped and lanthanide Doped Phosphor for light emitting diodes application
Journal of Solid State Chemistry, 2012Co-Authors: V H Romero, E De La Rosa, Pedro Salas, J J VelazquezsalazarAbstract:In this paper, we report the obtained strong broadband blue photoluminescence (PL) emission centered at 427 nm for unDoped BaZrO3 observed after 266 nm excitation of submicron crystals prepared by hydrothermal/calcinations method. This emission is enhanced with the introduction of Tm3+ ions and is stronger than the characteristic PL blue emission of such lanthanide. The proposed mechanism of relaxation for host lattice emission is based on the presence of oxygen vacancies produced during the synthesis process and the charge compensation due to the difference in the electron valence between dopant and substituted ion in the host. Brilliant white light emission with a color coordinate of (x=0.29, y=0.32) was observed by combining the blue PL emission from the host with the green and red PL emission from Tb3+ and Eu3+ ions, respectively. The color coordinate can be tuned by changing the ratio between blue, green and red band by changing the concentration of lanthanides.
Jing Wang - One of the best experts on this subject based on the ideXlab platform.
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eu3 Doped Phosphor in glass a route toward tunable multicolor materials for near uv high power warm white leds
Advanced Optical Materials, 2017Co-Authors: Jiankun Deng, Wei Li, Haoran Zhang, Haiming Zhang, Jing WangAbstract:A novel route toward tunable multicolor materials through Phosphor-in-glass (PiG) technology is proposed in this work. Before that, an ultrastable Eu3+-Doped precursor luminescent glass frit without thermal quenching in the temperature range of 80–480 K is developed to serve as an encapsulant that not only protects the embedded Phosphor but also provides the red-emitting component for the PiG. By adjusting the mass ratio of Sr4Al14O25:Eu2+ Phosphor to glass frit, a series of tunable multicolor Eu3+-Doped PiG is obtained and exhibits a good resistance to the harsh conditions. Meanwhile, the luminescent color of Eu3+-Doped PiG can be modified by changing the excitation wavelength or ambient temperature. Finally, corresponding Eu3+-Doped PiG encapsulated high-power light-emitting diodes are further fabricated, especially the warm white-light-emitting diodes (WLEDs), showing good color stability under different drive currents and with different periods of operating time. All these results indicate that Eu3+-Doped PiG is a potential color converter applied in the high-power warm-WLEDs and the route above opens up a facile and potential approach to obtain multicolor materials.
Anurag Pandey - One of the best experts on this subject based on the ideXlab platform.
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Colour emission tunability in Ho^3+–Tm^3+–Yb^3+ co-Doped Y_2O_3 upconverted Phosphor
Applied Physics B, 2012Co-Authors: Anurag PandeyAbstract:The frequency upconversion (UC) emission throughout the visible region from the Y_2O_3:Ho^3+–Tm^3+–Yb^3+ co-Doped Phosphors synthesized by using low temperature combustion process upon excitation with a diode laser operating at 980 nm have been presented. The colour emission tunability in co-Doped Phosphor has been observed on increasing the pump power and seen by the naked eyes. The tunability in colour emission has also been visualized by CIE chromaticity diagram. The variation in UC emission intensity of the ^1G_4 → ^3H_6 (Tm^3+) and ^5F_3 → ^5I_8 (Ho^3+) transitions lying in the blue region has been monitored with increase in the pump power and marked that their ratio can be used to determine the temperature. The developed Phosphor has been used to record fingerprints. The observed most intense visible colour emission from the developed material may be used for photodynamic therapy and as an alternative of traditional fluorescent biolabels.
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Colour emission tunability in Ho 3+ –Tm 3+ –Yb 3+ co-Doped Y 2 O 3 upconverted Phosphor
Applied Physics B, 2012Co-Authors: Anurag PandeyAbstract:The frequency upconversion (UC) emission throughout the visible region from the Y2O3:Ho3+–Tm3+–Yb3+ co-Doped Phosphors synthesized by using low temperature combustion process upon excitation with a diode laser operating at 980 nm have been presented. The colour emission tunability in co-Doped Phosphor has been observed on increasing the pump power and seen by the naked eyes. The tunability in colour emission has also been visualized by CIE chromaticity diagram. The variation in UC emission intensity of the 1G4 → 3H6 (Tm3+) and 5F3 → 5I8 (Ho3+) transitions lying in the blue region has been monitored with increase in the pump power and marked that their ratio can be used to determine the temperature. The developed Phosphor has been used to record fingerprints. The observed most intense visible colour emission from the developed material may be used for photodynamic therapy and as an alternative of traditional fluorescent biolabels.