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Title: Energy transfer and heat-treatment effect of photoluminescence in Eu{sup 3+}-doped TbPO{sub 4} nanowires

Abstract

We have successfully synthesized Eu{sup 3+}-doped TbPO{sub 4} nanowires, which are orderly organized to form bundle-like structure. A thermal treatment up to 600 deg. C does not modify the size, shape and structure of as-synthesized sample. Due to the energy overlap between Tb{sup 3+} and Eu{sup 3+}, an efficient energy transfer occurs from Tb{sup 3+} to Eu{sup 3+}. The effects of Eu{sup 3+} concentration and thermal treatment on the luminescent properties of Eu{sup 3+} are investigated. The increase of Eu{sup 3+} concentration leads to the increase of the energy transfer efficiency from Tb{sup 3+} to Eu{sup 3+}, but also enhances the probability of the interaction between neighboring Eu{sup 3+}, which results in the concentration quenching. With the heat-treatment, the luminescence of Eu{sup 3+} presents an obvious increase, but almost no change for the luminescence of Tb{sup 3+}. This difference is explained based on the TGA, DTA, and fluorescent decay dynamics analyses. - Graphical abstract: The energy transfer from Tb{sup 3+} to Eu{sup 3+} occurs in the Eu-doped TbPO{sub 4} nanowires synthesized by the hydrothermal route.

Authors:
 [1];  [2];  [2];  [3]
  1. Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033(China), E-mail: weihdi@yahoo.com.cn
  2. Key Laboratory of Excited State Processes, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China)
  3. Department of Physics, Dalian Maritime University, Dalian 116026 (China)
Publication Date:
OSTI Identifier:
21015672
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 180; Journal Issue: 2; Other Information: DOI: 10.1016/j.jssc.2006.11.006; PII: S0022-4596(06)00590-1; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DIFFERENTIAL THERMAL ANALYSIS; DOPED MATERIALS; ENERGY TRANSFER; EUROPIUM IONS; HEAT TREATMENTS; HYDROTHERMAL SYNTHESIS; PHOTOLUMINESCENCE; QUANTUM WIRES; QUENCHING; TERBIUM IONS; TERBIUM PHOSPHATES; THERMAL GRAVIMETRIC ANALYSIS

Citation Formats

Di Weihua, Wang Xiaojun, Zhu Peifeng, and Chen Baojiu. Energy transfer and heat-treatment effect of photoluminescence in Eu{sup 3+}-doped TbPO{sub 4} nanowires. United States: N. p., 2007. Web.
Di Weihua, Wang Xiaojun, Zhu Peifeng, & Chen Baojiu. Energy transfer and heat-treatment effect of photoluminescence in Eu{sup 3+}-doped TbPO{sub 4} nanowires. United States.
Di Weihua, Wang Xiaojun, Zhu Peifeng, and Chen Baojiu. Thu . "Energy transfer and heat-treatment effect of photoluminescence in Eu{sup 3+}-doped TbPO{sub 4} nanowires". United States. doi:.
@article{osti_21015672,
title = {Energy transfer and heat-treatment effect of photoluminescence in Eu{sup 3+}-doped TbPO{sub 4} nanowires},
author = {Di Weihua and Wang Xiaojun and Zhu Peifeng and Chen Baojiu},
abstractNote = {We have successfully synthesized Eu{sup 3+}-doped TbPO{sub 4} nanowires, which are orderly organized to form bundle-like structure. A thermal treatment up to 600 deg. C does not modify the size, shape and structure of as-synthesized sample. Due to the energy overlap between Tb{sup 3+} and Eu{sup 3+}, an efficient energy transfer occurs from Tb{sup 3+} to Eu{sup 3+}. The effects of Eu{sup 3+} concentration and thermal treatment on the luminescent properties of Eu{sup 3+} are investigated. The increase of Eu{sup 3+} concentration leads to the increase of the energy transfer efficiency from Tb{sup 3+} to Eu{sup 3+}, but also enhances the probability of the interaction between neighboring Eu{sup 3+}, which results in the concentration quenching. With the heat-treatment, the luminescence of Eu{sup 3+} presents an obvious increase, but almost no change for the luminescence of Tb{sup 3+}. This difference is explained based on the TGA, DTA, and fluorescent decay dynamics analyses. - Graphical abstract: The energy transfer from Tb{sup 3+} to Eu{sup 3+} occurs in the Eu-doped TbPO{sub 4} nanowires synthesized by the hydrothermal route.},
doi = {},
journal = {Journal of Solid State Chemistry},
number = 2,
volume = 180,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}
  • As a first step, we have synthesized and optically characterized a systematic series of one-dimensional (1D) single-crystalline Eu³⁺-activated alkaline-earth metal tungstate/molybdate solid solution composite CaW₁₋ xMo xO₄ (0 ≤ ‘x’ ≤ 1) nanowires of controllable chemical composition using a modified template-directed methodology under ambient room-temperature conditions. Extensive characterization of the resulting nanowires has been performed using X-ray diffraction, electron microscopy, and optical spectroscopy. The crystallite size and single crystallinity of as-prepared 1D CaW₁₋ xMo xO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) solid solution composite nanowires increase with increasing Mo component (‘x’). We note a clear dependence of luminescence output uponmore » nanowire chemical composition with our 1D CaW₁₋ xMo xO₄: Eu³⁺ (0 ≤ ‘x’ ≤ 1) evincing the highest photoluminescence (PL) output at ‘x’ = 0.8, amongst samples tested. Subsequently, coupled with either zero-dimensional (0D) CdS or CdSe quantum dots (QDs), we successfully synthesized and observed charge transfer processes in 1D CaW1-xMoxO4: Eu3+ (‘x’ = 0.8) – 0D QD composite nanoscale heterostructures. Our results show that CaW₁₋ xMo xO₄: Eu³⁺ (‘x’ = 0.8) nanowires give rise to PL quenching when CdSe QDs and CdS QDs are anchored onto the surfaces of 1D CaW₁₋ xMo xO₄: Eu³⁺ nanowires. The observed PL quenching is especially pronounced in CaW₁₋ xMo xO₄: Eu³⁺ (‘x’ = 0.8) – 0D CdSe QD heterostructures. Conversely, the PL output and lifetimes of CdSe and CdS QDs within these heterostructures are not noticeably altered as compared with unbound CdSe and CdS QDs. The difference in optical behavior between 1D Eu³⁺ activated tungstate and molybdate solid solution nanowires and the semiconducting 0D QDs within our heterostructures can be correlated with the relative positions of their conduction and valence energy band levels. We propose that the PL quenching can be attributed to a photo-induced electron transfer process from CaW₁₋ xMo xO₄: Eu³⁺ (‘x’ = 0.8) to both CdSe and CdS QDs, an assertion supported by complementary NEXAFS measurements.« less
  • We report on Tb{sup 3+} as efficient sensitizer for red photoemission from Mn{sup 2+}-centers in ZnO-B{sub 2}O{sub 3}-Al{sub 2}O{sub 3}-Si{sub 2}O-Na{sub 2}O-SrO glasses and corresponding gahnite glass ceramics. In comparison to singly or co-doped glasses, the glass ceramics exhibit significantly increased emission intensity. Structural considerations, ESR, and dynamic luminescence spectroscopy indicate partial incorporation of Mn{sup 2+} as well as Tb{sup 3+} into the crystalline phase, the former on octahedral Zn{sup 2+}-sites. Interionic distance and charge transfer probability between both species depend on crystallization conditions. This enables control of the energy transfer process and, hence, tunability of the color of photoemissionmore » by simultaneous emission from Tb{sup 3+} and Mn{sup 2+} centers. Concentration quenching in Mn{sup 2+}-singly doped materials was found at a critical dopant concentration of about 1.0 mol%. The energy transfer process was studied in detail by dynamic as well as static luminescence spectroscopy. Spectroscopic results suggest the application of the studied materials as single or dual-mode emitting phosphor for luminescent lighting. - Graphical abstract: In the prepared Tb{sup 3+}/Mn{sup 2+} codoped glass ceramics containing gahnite (ZnAl{sub 2}O{sub 4}) nanocrystals, the luminescence color is changed from green light to yellowish-red light with an increase in Mn{sup 2+} concentration due to enhanced energy transfer from Tb{sup 3+} to Mn{sup 2+} ions. This tunability should have potential applications in solid state lighting to produce white light, which can be obtained by appropriately optimizing the ratio of Tb{sup 3+}/Mn{sup 2+} ions under UV(350 nm) excitation. Highlights: > Photoluminescence from Mn{sup 2+} and Tb{sup 3+} singly and co-doped glasses and gahnite glass ceramics was studied. > Occurrence of energy transfer from Tb{sup 3+} to Mn{sup 2+} was confirmed. > Luminescence color tunability is achieved by varying dopant concentration and crystallization parameters.« less
  • A series of red-emitting phosphors Eu{sup 3+}-doped M{sub 2}Gd{sub 4}(MoO{sub 4}){sub 7} (M=Li, Na) have been successfully synthesized at 850 Degree-Sign C by solid state reaction. The excitation spectra of the two phosphors reveal two strong excitation bands at 396 nm and 466 nm, respectively, which match well with the two popular emissions from near-UV and blue light-emitting diode chips. The intensity of the emission from {sup 5}D{sub 0} to {sup 7}F{sub 2} of M{sub 2}(Gd{sub 1-x}Eu{sub x}){sub 4}(MoO{sub 4}){sub 7} phosphors with the optimal compositions of x=0.85 for Li or x=0.70 for Na is about five times higher thanmore » that of Y{sub 2}O{sub 3}:Eu{sup 3+}. The quantum efficiencies of the entitled phosphors excited under 396 nm and 466 nm are also investigated and compared with commercial phosphors Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+} and Y{sub 3}A{sub 5}O{sub 12}:Ce{sup 3+}. The experimental results indicate that the Eu{sup 3+}-doped M{sub 2}Gd{sub 4}(MoO{sub 4}){sub 7} (M=Li, Na) phosphors are promising red-emitting phosphors pumped by near-UV and blue light. - Graphical Abstract: The intensity of the red emission of M{sub 2}(Gd{sub 1-x}Eu{sub x}){sub 4}(MoO{sub 4}){sub 7} (M=Li, Na) phosphors with the optimal compositions is about five times higher than that of Y{sub 2}O{sub 3}:Eu{sup 3+}. Highlights: Black-Right-Pointing-Pointer Two novel Eu{sup 3+}-doped red phosphors (Na{sub 2}Gd{sub 4}(MoO{sub 4}){sub 2}, Li{sub 2}Gd{sub 4}(MoO{sub 4}){sub 7}) were synthesized. Black-Right-Pointing-Pointer Their emission intensities are about five times higher than that of Y{sub 2}O{sub 3}:Eu{sup 3+}. Black-Right-Pointing-Pointer Their quantum efficiencies are higher than that of commercial red phosphor Sr{sub 2}Si{sub 5}N{sub 8}:Eu{sup 2+}.« less
  • In this work, we used the solution precipitation route to synthesize Eu{sup 3+}-doped YPO{sub 4}.nH{sub 2}O nanowires. The structure, morphology, composition, thermal behavior, and photoluminescence of as-synthesized product were characterized by X-ray diffraction (XRD), thermogravimetric and differential thermal analysis (TG/DTA), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopic (FE-SEM) and photoluminescence (PL) spectra. The dependence of the structure, morphology, composition and luminescent properties on the thermal treatment was investigated. The results indicate that the aqueous synthesis has a better control on the structure, morphology, composition of the products, and that the heat treatment inducesmore » the transitions of the structure, composition, and luminescent properties. - Graphical abstract: The emission efficiency of the sample annealed at 250 deg. C is about six times as high as that of as-synthesized sample. This is attributed primarily to the coordinated water as the nonradiative relaxation pathways in the as-synthesized sample.« less
  • The relationship between the photoluminescence properties and the crystal structure of undoped, Eu{sup 3+} or/ and Tm{sup 3+} singly or codoped Ca{sub 9}La(VO{sub 4}){sub 7} (CLaVO) samples was discussed. Under the excitation of UV light, CLaVO:Tm{sup 3+}, CLaVO, and CLaVO:Eu{sup 3+} exhibit the characteristic emissions of Tm{sup 3+} ({sup 1}G{sub 4}→{sup 3}H{sub 6}, blue), O{sup 2−}→V{sup 5+} charge transfer (CT), and Eu{sup 3+} ({sup 5}D{sub 0}→{sup 7}F{sub 2}, red), respectively. By adjusting the doping concentration of Tm{sup 3+} and Eu{sup 3+} ions in CLaVO, a natural white emission in a single composition with the color temperature at 6181 K wasmore » obtained. Based on the dielectric theory of complex crystal, the chemical bond parameters of La-O and V-O bonds were quantitatively calculated. The standard deviation of environmental factor of every bond (EFSD), which can be expressed as σ(h{sub e{sub i}})=√((1/N)∑{sub i=1}{sup N}(h{sub e{sub i}}−μ){sup 2}) (h{sub e{sub i}}=(f{sub c{sub i}}α{sub b{sub i}}){sup 1/2}Q{sub B{sub i}} and μ=(1/N)∑{sub i=1}{sup N}h{sub e{sub i}}), was proposed to quantitatively express the distortion degree of VO{sub 4}{sup 3−} from that of an ideal tetrahedron. The maximum change of EFSD comes from the [VO{sub 4}]{sup −} tetrahedra in CLaVO sample by comparison with that of EFSD of isostructural Ca{sub 9}Gd(VO{sub 4}){sub 7}. This is possible the key reason that the undoped CLaVO sample has self-activated emission while the self-activated emission of its isostructural Ca{sub 9}Gd(VO{sub 4}){sub 7} sample cannot be found. The quantitative calculation also demonstrated that the broad excitation bands at 319 nm in CLaVO:Tm and at 335 nm in CLaVO:Eu were due to the O-V2 and O-V3 (overlap with O-V2) CT, not the CT energy of O{sup 2−}-Eu1{sup 3+} (O{sup 2−}-Tm1{sup 3+}), O{sup 2−}-Eu2{sup 3+} (O{sup 2−}-Tm2{sup 3+}), and O{sup 2−}-Eu3{sup 3+} (O{sup 2−}-Tm3{sup 3+}). The environmental factors surrounding the atoms V1, V2 and V3 were calculated to be 1.577, 1.6379 and 1.7554, respectively. It can be demonstrated that the excitation spectra at 319 nm for CLaVO:Tm and 335 nm for CLaVO:Eu came from the O-V2 and O-V3 CT, respectively. - Graphical abstracts: The relationship between the photoluminescence properties and the crystal structure of undoped, Eu{sup 3+} or/ and Tm{sup 3+} singly or codoped Ca{sub 9}La(VO{sub 4}){sub 7} (CLaVO) samples was discussed experimentally and theoretically. - Highlights: ●The photoluminescence properties of Ca{sub 9}La(VO{sub 4}){sub 7}:Eu, Tm were measured. ●The tunable color including white emission can be obtained. ●The important chemical bond parameters of O-V were calculated quantitatively. ●The standard deviation of environmental factor of every bond was proposed. ●The theoretical analysis of the self-activated emission for Ca{sub 9}La(VO{sub 4}){sub 7} was given.« less