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Preparation and luminescence characteristics of Eu2+ activated silicate phosphor
Preparation and luminescence characteristics of Eu^2+ activated silicate phosphor

Li Pan-Lai,Yang Zhi-Ping,Wang Zhi-Jun,Guo Qing-Lin,
李盼来
,杨志平,王志军,郭庆林

中国物理 B , 2008,
Abstract: This paper synthesizes the Sr发光形状 发光二极管 硅酸盐 无机发光材料Project supported by Hebei Provincial Technology Development Foundation of China (Grant No 51215103b).2007-07-122007-07-19This paper synthesizes the Sr2SiO4:Eu^2+ phosphor by high temperature solid-state reaction. The emission spectrum of Sr2SiO4 : Eu^2+ shows two bands centred at 480 and 547 nm, which agree well with the calculation values of emission spectrum, and the location of yellow emission of Sr2SiO4 : Eu^2+ is influenced by the Eu^2+ concentration. The excitation spectrum for 547 nm emission has two bands at 363 and 402 nm. The emission spectrum of white light emitting diodes (w-LEDs) based on Sr2SiO4 : Eu^2+ phosphor + InGaN LED was investigated.College of Physics Science & Technology, Hebei University, Baoding 071002, China;College of Physics Science & Technology, Hebei University, Baoding 071002, China;College of Physics Science & Technology, Hebei University, Baoding 071002, China;College of Physics Science & Technology, Hebei University, Baoding 071002, ChinaCorresponding author. E-mail: lipanlai@sohu.com/qk/85823A/200803/26618926.htmlwhite LED, Sr2SiO4:Eu2+, luminescence characteristics7855This paper synthesizes the Sr发光形状 发光二极管 硅酸盐 无机发光材料Project supported by Hebei Provincial Technology Development Foundation of China (Grant No 51215103b).2007-07-122007-07-19This paper synthesizes the Sr2SiO4:Eu^2+ phosphor by high temperature solid-state reaction. The emission spectrum of Sr2SiO4 : Eu^2+ shows two bands centred at 480 and 547 nm, which agree well with the calculation values of emission spectrum, and the location of yellow emission of Sr2SiO4 : Eu^2+ is influenced by the Eu^2+ concentration. The excitation spectrum for 547 nm emission has two bands at 363 and 402 nm. The emission spectrum of white light emitting diodes (w-LEDs) based on Sr2SiO4 : Eu^2+ phosphor + InGaN LED was investigated.College of Physics Science & Technology, Hebei University, Baoding 071002, China;College of Physics Science & Technology, Hebei University, Baoding 071002, China;College of Physics Science & Technology, Hebei University, Baoding 071002, China;College of Physics Science & Technology, Hebei University, Baoding 071002, ChinaCorresponding author. E-mail: lipanlai@sohu.com/qk/85823A/200803/26618926.htmlwhite LED, Sr2SiO4:Eu2+, luminescence characteristics7855This paper synthesizes the Sr$_{2}$SiO$_{4}$\,:\,Eu$^{2 + }$ phosphor by high temperature solid-state reaction. The emission spectrum of Sr$_{2}$SiO$_{4}$\,:\,Eu$^{2 + }$ shows two bands centred at 480 and 547\,nm, which agree well with the calculation values of emission spectrum, and the location of yellow emission of Sr$_{2}$SiO$_{4}$\,:\,Eu$^{2 + }$ is influenced by the Eu$^{2 + }$ concentration. The excitation spectrum for 547\,nm emission has two bands at 363 and 402\,nm. The emission spectrum of white light emitting diodes (w-LEDs) based on Sr$_{2}$SiO$_{4}$\,:\,Eu$^{2 + }$ phosphor + InGaN LED was investigated.
Luminescence characteristics of Eu2+ activated Ca2SiO4 Sr2SiO4 and Ba2SiO4 phosphorsfor white LEDs

Wang Zhi-Jun,Yang Zhi-Ping,Guo Qing-Lin,Li Pan-Lai,Fu Guang-Sheng,

中国物理 B , 2009,
Abstract: This paper investigates the luminescence characteristics of Eu2+ activated Ca2SiO4, Sr2SiO4 and Ba2SiO4 phosphors. Two emission bands are assigned to the f--d transitions of Eu2+ ions doped into two different cation sites in host lattices, and show different emission colour variation caused by substituting M2+ cations for smaller cations. This behaviour is discussed in terms of two competing factors of the crystal field strength and covalence. These phosphors with maximum excitation of around 370nm can be applied as a colour-tunable phosphor for light-emitting diodes (LEDs) based on ultraviolet chip/phosphor technology.
Luminescence Studies of Eu3+ Doped Calcium Bromofluoride Phosphor  [PDF]
Jagjeet Kaur,Yogita Parganiha,Vikas Dubey
Physics Research International , 2013, DOI: 10.1155/2013/494807
Abstract: The present paper reports photoluminescence (PL) and thermoluminescence (TL) properties of rare earth-doped calcium bromo-fluoride phosphor. The europium (Eu3+) was used as rare earth dopant. The phosphor was prepared by Solid state reaction method (conventional method). The PL emission spectrum of the prepared phosphor shows intense peaks in the red region at 611?nm for 5D0→7F2 transitions, and the PL excitation spectra show a broad band located around 220–400?nm for the emission wavelength fixed at 470?nm. The TL studies were carried out after irradiating the phosphor by UV rays with different exposure time. The glow peak shows second-order kinetics. The present phosphor can act as host for red light emission in display devices. 1. Introduction Rare earth-doped phosphors have been the center of attraction as luminescent materials from the last many decades. These phosphors have caused great attention to use as the host materials for X-ray screens, neutron detectors, alpha-particle scintillators, and so forth, due to their high luminescence efficiency and are also used as emissive materials in various display devices like LCD, FET, and CRT or as illumination sources [1–3]. Spectroscopic studies of these phosphors play a vital role in characterizing the specific luminescence properties such as photoluminescence and thermoluminescence. The rare earths are usually incorporated in these materials as divalent or trivalent cation for the realization of optically active materials in photonics and optoelectronic applications. The europium is efficiently used as luminescent center in phosphors for various purposes. Phosphors doped with europium ions are of greater importance for observing red colors on the monitors of various display devices [4]. 2. Experimental Method By solid state reaction process, CaF2, KBr, and Eu2O3 were mixed in stoichiometric ratio by dry grinding in mortar and pestle for nearly 45 minutes. The mixture is taken in quartz boat and is fired in air at 730°C for 3 hours in presence of urea. The photoluminescence studies were carried out using RF5301 spectrophotofluorometer in the wavelength range 400–650?nm at room temperature. The thermoluminescence studies were carried out using TLD reader I1009 supplied by Nucleonix System Pvt. Ltd., Hyderabad [5]. The sample was irradiated by UV radiation 365?nm. The heating rate used for TL measurement is 3°C/s. Curves were analyzed by using computer glow curve deconvolution program. 3. Result and Discussion 3.1. Photoluminescence Studies 3.1.1. PL Excitation Spectra Figure 1 shows the PL excitation
Luminescence characteristics of Eu3+ activated borate phosphor for white light emitting diode

Li Pan-Lai,Yang Zhi-Ping,Wang Zhi-Jun,Guo Qing-Lin,

中国物理 B , 2008,
Abstract: In this paper, the Sr3Y2 (BO3)4:Eu3+ phosphor was synthesized by high temperature solid-state reaction method and the luminescence characteristics were investigated. The emission spectrum exhibits one strong red emission at 613nm corresponding to the electric dipole 5D0--7F2 transition of Eu3+ under 365nm excitation, this is because Eu3+ substituted for Y3+ occupied the non-centrosymmetric position in the crystal structure of Sr3Y2 (BO3)4. The excitation spectrum indicates that the phosphor can be effectively excited by ultraviolet (254nm, 365nm and 400nm) and blue (470nm) light. The effect of Eu3+ concentration on the red emission of Sr3Y2 (BO3)4:Eu3+ was measured, the result shows that the emission intensities increase with increasing Eu3+ concentration, then decrease. The Commission Internationale del'Eclairage chromaticity (x, y) of Sr3Y2(BO3)4:Eu3+ phosphor is (0.640,0.355) at 15 mol% Eu3+.
Effective Red Compensation of ?:? Phosphor by Codoping Ions and Its Energy Transfer  [PDF]
Le Zhang,Zhou Lu,Pengde Han,Lixi Wang,Qitu Zhang
Journal of Nanomaterials , 2012, DOI: 10.1155/2012/848274
Abstract: 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 were ′-Sr2SiO4. The codoping concentration range of Mn2+ was ?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)2SiO4 phosphor with high and almost pure white emission has great potential to act as a single-matrix white phosphor for white LEDs. 1. Introduction White light emitting diodes have attracted more attention due to their potential applications in extensive fields, such as device indicators, backlight, automobile headlights, and general illumination [1–4]. Current white LEDs are composed of blue-emitting GaN chip and yellow-emitting YAG?:?Ce phosphor. However, YAG?:?Ce has a deficient red emission, leading the white LEDs to have a low color rendering index (CRI < 80) [5]. To enrich the red emission, the phosphor blend of YAG?:?Ce and a red emitting phosphor is generally applied [6, 7]. Another technology is the combination of tricolor phosphors with an UV-LED chip. The above phosphor mixtures give fluorescence reabsorption and nonuniformity of luminescence properties, resulting in a loss of luminous efficiency and time-dependent shift of the color point. Therefore, a single-phase phosphor with direct white light emission is desirable [8–11]. At present, the most of this kind phosphors have at least two luminescent centers, such as Eu2+/Mn2+ [3, 12, 13], Ce3+/Eu2+ [8], or Eu2+ (in different lattice sites) [9]. As the natural white light emission ions, Dy3+ ions have two dominant emission bands of blue (485?nm, 4F9/2 → 6H15/2) and yellow (570?nm, 4F9/2 → 6H13/2) [14, 15]. Recently, Dy3+ doped alkaline earth orthosilicates (Sr2SiO4?:?Dy3+) powders have attracted much attention due to its excellent emission characteristic, single luminescent center, and high absorption efficiency in the UV region [16–18]. This phosphor can emit white light with CIE chromaticity
Preparation and Luminescence Characteristics of Ca3Y2(BO3)4:Eu3+ Phosphor
Preparation and Luminescence Characteristics of Ca3Y2(BO3)4:Eu^3+ Phosphor

LI Pan-Lai,YANG Zhi-Ping,WANG Zhi-Jun,Guo Qing-Lin,
李盼来
,杨志平,王志军,郭庆林

中国物理快报 , 2007,
Abstract: Ca3Y2(BO3)4:Eu3+ phosphor is synthesized by high temperature solid-state reaction method, and the luminescence characteristics are investigated. The emission spectrum exhibits two strong red emissions at 613 and 621nm corresponding to the electric dipole 5D0--7F2 transition of Eu3+ under 365nm excitation, the reason is that Eu3+ substituting for Y3+ occupies the non-centrosymmetric position in the crystal structure of Ca3Y2(BO3)4. The excitation spectrum for 613nm indicates that the phosphor can be effectively excited by ultraviolet (UV) (254nm, 365nm and 400nm) and blue (470nm) light. The effect of Eu3+ concentration on the emission intensity of Ca3Y2(BO3)4:Eu3+ phosphor is measured, the result shows that the emission intensities increase with increasing Eu3+ concentration, then decrease. The CIE colourcoordinates of Ca3Y2(BO3)4:Eu3+ phosphor is (0.639, 0.357) at 15mol% Eu3+.
Preparation and luminescence characteristics of Sr3SiO5:Eu2+ phosphor for white LED
PanLai Li,ZhiPing Yang,ZhiJun Wang,QingLin Guo,Xu Li
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-0044-8
Abstract: The Sr3SiO5:Eu2+ phosphor was synthesized by high temperature solid-state reaction. The emission spectrum of Sr3SiO5:Eu2+ shows two bands centered at 487 and 575 nm, which well agree with the theoretic values of emission spectrum. The excitation spectrum for 575 nm emission center has several excitation bands at 365, 418, 458 and 473 nm. And the results show that the emission spectrum of Sr3SiO5:Eu2+ is influenced by the Eu2+ concentration. The relative emission spectra of the white-emitting InGaN-based YAG:Ce3+ LED and Sr3SiO5:Eu2+ LED were investigated. The results show that the color development of InGaN-based Sr3SiO5:Eu2+ is better than that of InGaN-based YAG:Ce3+, and the CIE chromaticity of InGaN-based Sr3SiO5:Eu2+ is (x=0.348, y=0.326).
Preparation and luminescence characteristics of Sr3SiO5:Eu2+ phosphor for white LED

LI PanLai,YANG ZhiPing,WANG ZhiJun,GUO QingLin,LI Xu,

科学通报(英文版) , 2008,
Abstract: The Sr3SiO5:Eu2+ phosphor was synthesized by high temperature solid-state reaction. The emission spectrum of Sr3SiO5:Eu2+ shows two bands centered at 487 and 575 nm, which well agree with the theoretic values of emission spectrum. The excitation spectrum for 575 nm emission center has several excitation bands at 365, 418, 458 and 473 nm. And the results show that the emission spectrum of Sr3SiO5:Eu2+ is influenced by the Eu2+ concentration. The relative emission spectra of the white-emitting InGaN-based YAG:Ce3+ LED and Sr3SiO5:Eu2+ LED were investigated. The results show that the color development of InGaN-based Sr3SiO5:Eu2+ is better than that of InGaN-based YAG:Ce3+, and the CIE chromaticity of InGaN-based Sr3SiO5:Eu2+ is (x=0.348, y=0.326). Supported by Hebei Provincial Technology Development Foundation (Grant No. 51215103b)
Synthesis, characterization and luminescence properties of long afterglow Phosphor Ba4Al14O25:Eu,Dy  [cached]
Fatih Mehmet Emen,Nevzat Külcü,Ahmet Necmeddin Yaz?c?
European Journal of Chemistry , 2010, DOI: 10.5155/eurjchem.1.1.28-32.8
Abstract: Long persistent afterglow phosphor, Ba4Al14O25:Eu2+,Dy3+ was prepared at high temperature by a solid state reaction in a weak reductive atmosphere. The crystal structure of Ba4Al14O25:Eu2+,Dy3+ has been determined as an orthorhombic Pmmm space group with a=18.200(6) , b=16.923(6) , c=5.131(21) , V=1580.3(9) 3 and Z=8. The reflectance measurement was obtained by using the Diffuse Reflectance Spectrophotometer and the band gap energy of the undoped host phase of Ba4Al14O25 was calculated by using Kubelka-Munk treatment on the diffuse reflectance spectra, and found to be 4.72 eV. The excitation and emission peaks are broad bands and the main emission peak at 520 nm with shoulder at 496 nm belongs to the intrinsic defect of the host and 4f65d1→4f7 transition of Eu2+, respectively. The afterglow decay curve implied that this phosphor contains fast and slow-decay processes. The thermoluminescence glow curve showed one dominant glow peak observed at 50 oC and two weak glow peaks at around 140 oC and 220 oC which are related to the defects at different trap depths.
Preparation mechanism and luminescence of Sr2SiO4: Eu phosphor from (Sr, Eu)CO3@SiO2 core-shell precursor  [PDF]
Yunsheng Hu, Weidong Zhuang, Jianhua Hao, Xiaowei Huang, Huaqiang He
Open Journal of Inorganic Chemistry (OJIC) , 2012, DOI: 10.4236/ojic.2012.21002
Abstract: Sr2SiO4: Eu phosphor for white light emitting diodes (LEDs) was synthesized by employing an as-prepared (Sr, Eu)CO3@SiO2 core-shell precursor as starting materials, and the effect of the core-shell precursor was also discussed on the crystal structure, particle morphology and luminescent properties of the resultant phosphor. The results showed that the hybrid β- and α′-Sr2SiO4: Eu phosphor with fine particle size and narrow distribution could be obtained at a lower firing temperature than that in conventional solidstate reaction method, and its formation mechanism was deduced to be (Sr, Eu)CO3 diffusion controlled reaction process. Responded to its hybrid crystal structure, this phosphor exhibited the combined luminescence of β- and α′-Sr2SiO4: Eu.
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