CHEMICAL PHYSICS LETTERS
·
2016
·
IF 1.86
Jiangyun Dai,Guoying Feng,Jiajia Yin,Chao Yang,Xianheng Yang,Hua Zhang,Hong Zhang,Shouhuan Zhou
NaGdF 4 nanocrystals with controlled shapes were synthesized in an ethylene glycol/deionized water hydrothermal reaction system. Through adjusting the solvent composition, the nanocrystals with nanosphere-, nanotube-, and nanorod-like morphology have been selectively synthesized. The change in the nucleation speed, the growth rates in different crystallographic direction and the aggregation driving forces induced different morphologies of the resulting nanocrystals. A possible mechanism of shape evolution depending on solvent composition was proposed. Photoluminescence spectra of NaGdF 4 :Nd 3+ nanocrystals exhibited characteristic emission of Nd 3+ using an excitation wavelength of 794 nm. Moreover, the nanotube-like nanocrystals exhibited the strongest fluorescence intensity and longest fluorescence decay time.
研究领域:
材料科学
·
光学
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产品关联
DOI
高影响因子
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2018
·Vol. 20
·期 23
·15835-15840
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IF 3.906
Jianning Jin,Hua Yu,Liying Guo,Jinjin Liu,Bing Wu,Yuao Guo,Yuting Fu,Lijuan Zhao
β-NaREF4 (RE: rare earth metals) is a peculiar crystal due to its intriguing disordered structure. This crystal is usually considered to have an average structure with a space group of P-6 (174). However, a long-term contradiction existing in this system is that the luminescence characteristics do not match the corresponding theoretical predictions based on the average structure. To resolve this contradiction, we proposed a reasonable local structure model clearly showing the local symmetry of the cations based on the measurement of the extended X-ray absorption fine structure of β-NaGdF4. We also observed an intrinsic distortion in the disordered structure that resulted from the disordered arrangement of the Na+ and Gd3+ cations. Furthermore, using Eu3+ as a photoluminescence probe, we concluded that the breakdown in the crystallographic site symmetry originated from the intrinsic distortion of these crystals. This work provides a comprehensive explanation for the contradiction observed in this system and a foundation for further investigations to understand such disordered structures.
研究领域:
材料科学
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晶体学
·
光谱学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
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2022
·Vol. 37
·期 3
·393-398
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IF 1.271
Hou Huayu,Gan Lin,Wang Youfa,Wang Wei
Nd 3+ -doped NaGdF 4 : Yb, Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method, and the effects of doping concentrations on the crystal structure, phase composition, and upconverted fluorescence intensity were also investigated. The results reveal that the introduction of Nd 3+ ions does not cause the transformation of the crystal phase, but induce the change of the unit cell parameters. Meanwhile, the fluorescence intensity of the synthesized nanocrystals when co-doped with 3 mol% Nd 3+ is the strongest under the excitation of 980 nm laser, which is 3.9 times that of the Nd 3+ -free doped nanoparticles, and the average size is 62.9 nm. And it is located in the blue area of the CIE coordinate diagram, and the corresponding color purity is 91.81% under the same experimental conditions. The resulting nanocrystals show the potential as excellent fluorescence labeling and in vivo imaging probes.
研究领域:
材料科学
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纳米技术
·
光学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Guangdong Wu,Juanqin Xue,Dashi Lei,Yanyan Zhou,Zhaoyuan Cao,Kang Ren,Qiang Bi,Zhihua Leng
Currently, upconversion nanoparticles (UCNPs) based photocatalysts have been extensively developed to improve solar energy utilization. However, the mechanisms underlying interfacial energy migration of upconversion photocatalyst remain unclear. Herein, a promising composite photocatalyst with complementary properties is designed by integrating β -NaGdF 4 :Yb 3+ /Er 3+ (NGFYE), CdS and multi-walled carbon nanotubes (MWCNTs). The morphology, structure and chemical properties of NGFYE@CdS/MWCNTs ternary photocatalyst are characterized. In addition, the existence of Förster resonance energy transfer process in NGFYE@CdS/MWCNTs photocatalysts, i.e., the migration of excitation energy from Er 3+ − 4 S 3/2 excitation level and higher excitation level (e.g., Er 3+ − 2 H 11/2 ) to CdS nanoparticles, was further confirmed by density functional theory (DFT) calculations. The optimized NGFYE@CdS/MWCNTs photocatalyst presents 71.65 % and 35.29 % degradation of tetracycline hydrochloride (TCH) and ciprofloxacin (CIP) under λ ≥ 800 nm irradiation for 3 h, respectively. This work not only illustrates the interfacial energy migration mechanism between NGFYE and CdS, but also provides insights for the rapid construction of heterojunction materials with efficient energy transfer interfaces.
研究领域:
材料科学
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环境科学
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理论化学
✓ 已验证
产品关联
DOI
高影响因子
CRYSTENGCOMM
·
2015
·Vol. 17
·期 31
·5900-5905
·
IF 4.034
Bin-Bin Ding,Kun Liu,Fu Zhang,Yang Wang,Sheng Cheng,Yang Lu,Hai-Sheng Qian
Upconversion fluorescent nanostructures with controlled sizes and morphologies have attracted much attention due to their potential and important applications in bioimaging, photodynamic therapy, solar cells and so on. In this work, we describe a facile successive process to fabricate β-NaGdF4:Yb,Er nanocrystals coated with an ultrathin layer of CaF2 with enhanced upconversion fluorescence and stability. The as-prepared β-NaGdF4:Yb,Er@CaF2 nanoparticles were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM, JEM 21000), fluorescence spectroscopy (Hitachi High-Technology Corporation, F-2700) and inductively coupled plasma atomic emission spectroscopy (ICP-AES). The as-prepared core–shell nanoparticles show enhanced upconversion fluorescence and superior magnetic resonance (MR) relaxivity. In addition, the as-prepared β-NaGdF4:Yb,Er@CaF2 nanoparticles show enhanced chemical stability after surface functionalization and transfer into aqueous solutions.
研究领域:
材料科学
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生物医学工程
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
Advanced Optical Materials
·
2026
·
IF 7.2
Yingjun Li,Dawei Sun,Haixin Liu,Hongxian Wei,Shasha Wang,Gejihu De
Lanthanide (Ln 3+ )-doped upconversion luminescent materials (UCLMs) have tremendous potential for applications in solar cells, optical sensors, and various other fields. However, their low luminescent efficiency and thermal stability remain key challenges that hinder their practical applications. Here, we introduce an innovative method for enhancing the upconversion luminescent efficiency of Er 3+ -activated UCLMs by constructing high-entropy fluoride hosts based on the β -NaGdF 4 framework—NaMF 4 (M = Na, Yb, Gd, Ca, La, Lu, or Y). The β -NaGdF 4 structure is preserved despite the decrease in the Gd 3+ concentration with an increase in the number of principal elements. High-entropy engineering introduces severe lattice distortion, which enhances the doping tolerance of the host for Er 3+ ions and significantly modifies the local crystal field around them. These changes result in enhanced emission intensity and a higher quantum yield. Optimum upconversion luminescence is observed for the high-entropy six-element composition at room temperature; the emission intensity and quantum yield are 2.5 times those of NaGdF 4 :20%Yb/2%Er. In addition, Er 3+ -activated high-entropy fluorides exhibit better thermal stability than NaGdF 4 :20%Yb/2%Er. These results demonstrate that high-entropy engineering is a promising approach for improving the luminescent performance of Ln 3+ -doped UCLMs.
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DOI
高影响因子
CRYSTENGCOMM
·
2020
·Vol. 22
·期 38
·6330-6338
·
IF 3.117
Chunyan Cheng,Yueshan Xu,Gejihu De,Jianxun Wang,Wei Wu,Yuexing Tian,Shasha Wang
Rare-earth doped upconversion nanoparticles (UCNPs) have attracted wide-ranging interest due to their potential applications in bioimaging and biolabeling, where a high emission intensity and small particle size are needed. However, common synthesis processes can be somewhat complex or require additional reactants, and the use of small-size NPs is limited by their weak luminescence intensity. In this work, uniform, monodisperse ∼5 nm β-NaGdF4:20% Yb/2% Er NPs were synthesized via a simple one-pot synthesis method in the high boiling-point solvents 1-octadecene (ODE) and oleic acid (OA) using a single dose of NaF at an ultralow NaF concentration of NaF/RE = 4. The effects of NaF/RE, the reaction temperature, and the reaction time on the size and phase of the particles were investigated. High-quality β-NaGdF4:20% Yb/2% Er@β-NaGdF4:20% Yb/10% Nd core–shell NPs with a size of ∼13 nm, enhanced UC luminescence, long UC lifetimes (τ) for green (τ ≈ 150 μs) and red (τ ≈ 105 μs) emission under 980 and 808 nm excitation, revealed via lifetime imaging, and obvious emission in the near-infrared (NIR) II region were synthesized. The synthesized core–shell NPs may result in a decrease in the overheating effect and allow for a deep penetration depth when further used for bioimaging applications. This work could inspire the synthesis of other high-quality RE-doped UCNPs via adding a single dose of a small amount of NaF and could lay the foundation for the use of Gd-based UCNPs in biomedical applications.
研究领域:
材料科学
·
生物医学工程
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DOI
高影响因子
EPL
·
2014
·Vol. 106
·期 4
·48001
·
IF 2.269
AiHua Li,Tengpeng Guan,Zhijun Sun
Upconversion nanophosphors (UCNPs) of lanthanide-doped efficient ternary fluoride (β-NaGdF4:Yb3+,Er3+) with sizes below 20 nm are synthesized in a facile solvothermal route. Upconversion luminescence (UCL) of the UCNPs is found to increase with increase of the nanoparticle size prepared at a higher solvothermal-treatment temperature, due to reduction of the surface defects. Interestingly, opposite size dependences of the red/green UCL intensity ratio are observed for the same series of UCNPs in different surface conditions, i.e., with increase of the nanoparticle size, the ratio decreases for as-prepared dry powders, but increases for moisturized counterparts after being exposed in air for some days, and interesting the ratio decreases again after annealing of the moisturized samples. The phenomenon is explained due to the effect of surface defects and adsorbed water molecules, respectively, dominating in nonradiative relaxations, which usually facilitate red UCL. The disclosed phenomenon clarifies some contradictory observations on UCL in the literature.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
RSC Advances
·
2018
·Vol. 8
·期 23
·12944-12950
·
IF 2.936
Yang Su,Li-Na Hao,Kun Liu,Jun Zhang,Liang Dong,Yunjun Xu,Yang Lu,Hai-Sheng Qian
Upconversion core–shell nanoparticles have attracted a large amount of attention due to their multifunctionality and specific applications. In this work, based on a NaGdF4 sub-10 nm ultrasmall nanocore, a series of core–shell upconversion nanoparticles with uniform size doped with Yb3+, Er3+ and NaDyF4 shells with different thicknesses were synthesized by a facile sequential growth process. NaDyF4 coated upconversion luminescent nanoparticles showed an obvious fluorescence quenching under excitation at 980 nm as a result of energy resonance transfer between Yb3+, Er3+ and Dy3+. NaGdF4:Yb,Er@NaDyF4 core–shell nanoparticles with ultrathin layer shells exhibited a better T1-weighted MR contrast.
研究领域:
材料科学
·
医学影像
·
纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry C
·
2018
·Vol. 6
·期 19
·5210-5217
·
IF 5.976
Shaohua Fan,Guojun Gao,Zhiquan Lin,Weichang Li,Sijun Fan,Shiyu Sun,Hongtao Sun,Lili Hu
High purity green up-conversion (UC) materials have wide applications in fluorescent labeling, plastic recycling and displays, etc. However, Yb3+/Er3+-based UC materials exhibit poor color purity of green light, and their output color is normally unstable under a variable excitation power density, which hinders their application in the aforementioned areas. Herein, we report the highly stable and efficient pure green UC of rod-like β-NaGdF4:Yb3+,Ho3+ submicro-crystals synthesized via a newly developed ion-exchange modified (IEM) method. IEM-derived NaGdF4:Yb3+,Ho3+ monodisperse submicro-crystals present not only a high-purity green output color (due to the large intensity ratio of green to red, IGreen/IRed ≈ 5) but also excellent color stability under varying conditions, such as excitation power density and doping concentration of Yb3+/Ho3+. More importantly, IEM arouses an enormously enhanced UC emission intensity of ∼3700-fold that of the precursor crystals (PC). The UC emission intensity of IEM β-NaGdF4:Yb3+,Ho3+ is ∼4 times stronger than that of its high temperature annealing (HTA) counterpart. The emission intensity of the single green band is ∼40% stronger than that of the IEM β-NaGdF4:20%Yb3+,2%Er3+ submicro-crystals. A proof-of-concept fluorescent labeling of clover patterns (15 × 12 mm) printed from NaGdF4:Yb3+,Ho3+ ink with stable and high purity green fluorescence is demonstrated under excitation with various power densities.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）