MATERIALS CHEMISTRY AND PHYSICS
·
2021
·
IF 4.094
Chengkai Zheng,Zaichun Sun,Weiwei Li,Yu Yang,Bingchu Mei
Dysprosium-doped strontium fluoride (Dy: SrF 2 ) nanopowders with the doping concentration of x mol% (x = 0.5, 1.0, 3.0, 5.0, 7.0, 9.0) were synthesized by chemical co-precipitation method, and the composition and morphologies of nanopowders were characterized by XRD and TEM. The results indicated that the grain size and lattice constants of the powders showed a decreasing trend. Dy:SrF 2 transparent ceramics were fabricated by vacuum hot pressing sintering. The transmittance of the ceramics reaches 86.14% in the visible light band while the Dy 3+ ion concentration is 3.0 mol%. Under the excitation of 349 nm, the two significant emission peaks located at 479 nm and 576 nm, which were corresponding to blue emission and yellow emission of Dy 3+ ion, respectively. The emission intensity firstly increased and then decreased with the amount of doping increasing. And the lifetimes decreased continuously with the Dy 3+ ion doping concentration increasing from 1.0 mol% to 9.0 mol%. According to the CIE chromaticity coordinates, Dy:SrF 2 transparent ceramics can achieve white light emission, and the SrF 2 ceramic with 7.0 mol% doping concentration of Dy 3+ ions was the closest to perfect white light. It demonstrates that Dy:SrF 2 transparent ceramics is a potential candidate for solid-state laser materials in visible band.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Zhiwei Zhou,Yongqiang Zhang,Xinwen Liu,Bingchu Mei,Liping Zhou,Jianchun Qin,Dan Yuan
0.5–5 % (atom percent) Nd 3+ -doped SrF 2 transparent ceramics were fabricated by hot-pressed sintering and the effects of Nd 3+ doping content on microstructure and spectral properties were studied. With Nd 3+ content increased from 0.5 % to 5 %, in-line transmittance of Nd:SrF 2 ceramic at 1060 nm increased from 15.8 % to 85.3 %. FE-SEM micrographs showed the grain growth was inhibited and the microstructure became more compact and homogenous. Emission spectra revealed that concentration quenching was occurred at Nd 3+ content of 1–2 %. Emission lifetime of 4 F 3/2 energy level monotonously decreased from 1805.4 μs to 19.6 μs. Evolution profiles of emission intensity and lifetime of Nd:SrF 2 transparent ceramic with Nd 3+ doping content were proposed. The appropriate Nd 3+ content for spectral properties of Nd:SrF 2 transparent ceramic was found around 1 %. The results demonstrated Nd:SrF 2 transparent ceramic has large emission lifetime and mild concentration quenching effect, indicating that Nd 3+ -doped SrF 2 transparent ceramics could be more promising gain media for all-solid-state lasers than other Nd 3+ -doped alkaline-earth fluorides.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2017
·
IF 2.238
Weiwei Li,Haijun Huang,Bingchu Mei,Jinghong Song
In this paper, ytterbium doped strontium fluoride (Yb: SrF 2 ) nanoparticles were synthesized by direct precipitation method. High-speed centrifugation was used to separate high sintering activity of nanopowders from powders with hard aggregated and large size. Using powders at different parts of the centrifugal tube as starting powders, Yb: SrF 2 transparent ceramics was fabricated by hot pressed (HP) method for the first time. Effects of morphology and particle size on the sinterability of Yb: SrF 2 nanopowders were investigated. The transmittance reached 77% at the wavelength of 1200 nm and pores stilled remained in the ceramics. The spectroscopic and thermal properties of Yb: SrF 2 transparent ceramics were also investigated. This paper provides an effective way to obtain well dispersed and high sinterability nanoparticles for SrF 2 ceramics sintering.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2021
·Vol. 28
·期 10
·1621-1628
·
IF 2.232
Yang Jun,Lin Yuan-hua,Guo Bing-shu,Wang Ming-shan,Chen Jun-chen,Ma Zhi-yuan,Huang Yun,Li Xing
The silicon-based material exhibits a high theoretical specific capacity and is one of the best anode for the next generation of advanced lithium-ion batteries (LIBs). However, it is difficult for the silicon-based anode to form a stable solid-state interphase (SEI) during Li alloy/de-alloy process due to the large volume change (up to 300%) between silicon and Li 4.4 Si, which seriously limits the cycle life of the LIBs. Herein, we use strontium fluoride (SrF 2 ) particle to coat the silicon-carbon (Si/C) electrode (SrF 2 @Si/C) to help forming a stable and high mechanical strength SEI by spontaneously embedding the SrF 2 particle into SEI. Meanwhile the formed SEI can inhibit the volume expansion of the silicon-carbon anode during the cycle. The electrochemical test results show that the cycle performance and the ionic conductivity of the SrF 2 @Si/C anode has been significantly improved. The X-ray photoelectron spectroscopy (XPS) analysis reveals that there are fewer electrolyte decomposition products formed on the surface of the SrF 2 @Si/C anode. This study provides a facile approach to overcome the problems of Si/C electrode during the electrochemical cycling, which will be beneficial to the industrial application of silicon-based anode materials.
研究领域:
材料科学
·
电化学
✓ 已验证
DOI
高影响因子
OPTICAL MATERIALS
·
2020
·
IF 2.779
Yiwei Gao,Bingchu Mei,Weiwei Li,Zhiwei Zhou,Zuodong Liu
Ytterbium-doped strontium fluoride (Yb: SrF 2 ) nanopowders with different amounts of Yb 3+ were synthesized by a co-precipitation method. XRD and FE-SEM measurements were used to characterize the phase composition and morphologies of these nanopowders. The Yb: SrF 2 nanopowders doped with 1–5 at.% Yb 3+ showed the same phase as pure SrF 2 , with a mean particle size of 20 nm. Transparent Yb: SrF 2 ceramics were fabricated by hot-pressing the nanopowders, and the transmittance of 1 at.% Yb: SrF 2 with a thickness of 2 mm was 85% at 1200 nm. The absorption spectra , luminescence spectra, and luminescence decays of the ceramics were also obtained. As the Yb 3+ doping amount increased, the absorption and emission intensities also increased, indicating the absence of a concentration quenching effect in the Yb: SrF 2 ceramics. However, the decay lifetimes decreased with increasing Yb 3+ content, and 1–5% Yb: SrF 2 transparent ceramics had decay lifetimes of 4.58, 3.48, 3.22, and 3.19 ms, respectively.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-10
·
IF 15.7
Cai Chongyang,Li Leipeng,Lv Xiaohuan,Li Huimin,Li Tao,Li Pei,Zhao Wenting,Zi Lingzhu,Feng Shiji,Fan Xuan,Zhang Hailei,Peng Dengfeng,Wang Feng,Qiu Jianrong,Yang Yanmin
Lanthanides-doped luminescent materials have gathered considerable attention due to their application potential in stress sensing, lighting and display, anti-counterfeiting technology and so forth. However, existing materials mainly cover the 380–1540 nm range, with slight extension to the UV region, impeding their applications in solar-blind imaging, background-free tracking, concealed communication, etc. To address this challenge, here we propose guidelines for far-UVC (200–230 nm) optical design. Accordingly, we achieve multi-stimulated far-UVC luminescence at ~222 nm in Pr 3+ -doped SrF 2 , stemming from the inter-configurational 4f5d → 4f 2 transition of Pr 3+ . Besides Pr 3+ , the SrF 2 host shows high tolerance to Ce 3+ , Nd 3+ , Sm 3+ , Eu 2+,3+ , Gd 3+ , Tb 3+ , Dy 3+ , Ho 3+ , Er 3+ , Tm 3+ and Yb 3+ , vastly extending the emission wavelength across the entire spectral range from 200 to 1700 nm. Particularly, these materials exhibit self-recoverable mechanoluminescence by direct mechanical excitation, along with thermally and mechanically stimulated emission after X-ray irradiation. We demonstrate that these lanthanides-doped SrF 2 crystals offer unique opportunities for high-contrast marking and structural health monitoring in complex environments.
研究领域:
光学材料
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光电子学
·
固体物理
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DALTON TRANSACTIONS
·
2016
·Vol. 45
·期 13
·5800-5807
·
IF 4.177
Ai-Hua Li,Mengyun Lü,Jun Yang,Lin Chen,Xiaohong Cui,Zhijun Sun
Sub-20 nm core–shell and water-soluble SrF2:Yb,Tm@CaF2:Gd heteronanoparticles with both upconversion luminescence (UCL) and magnetic resonance imaging (MRI) capabilities were designed and synthesized via a two-step hydrothermal method. In the design of the heteronanoparticles, SrF2:Yb,Tm nanoparticles with high UCL efficiency are chosen as the core material for strong UCL output; and by epitaxially coating the SrF2:Yb,Tm core particles with inert and biocompatible shells of CaF2:Gd, the core–shell heteronanoparticles are endowed with a magnetic capability (longitudinal relaxivity of 2.4 mM−1 s−1) for MRI, as well as an enhancement of the near infrared (NIR) UCL by 9.2 times. The aqueous dispersion of SrF2:Yb,Tm@CaF2:Gd heteronanoparticles with a concentration of 2.6 wt% can emit NIR UCL so as to be easily detected with a fiber optical spectrometer under illumination of a 975 nm laser diode with a power density of 8.8 W cm−2. Such a dispersion with a Gd3+ concentration of 0.0143 mM in the shell region of the heteronanoparticles can also generate the detectable quickening of longitudinal relaxation. The results promise the strong potential of this nanomaterial for applications in bioimaging as a dual-functional probe.
研究领域:
纳米技术
·
生物医学成像
·
材料科学
·
分子诊断
·
诊疗一体化
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
·
2025
·
IF 5.4
Zuodong Liu,Tingting Xiong,Chengwei Zhang,Qiyue Pan,Guo Zhang,Rui Liu,Yongsheng Yu,Peng Liu,Qiangshan Jing
A series of SrF 2 phosphors co-doped with Er 3+ and Y 3+ possessing regular polygon shapes were fabricated after calcination as-synthesized particles at 600 °C for 2 h. the crystal structure and morphology of the Er, Y:SrF 2 phosphors were identified. By incorporating the non-active Y 3+ ions as buffers into Er:SrF 2 phosphors, intense green up-conversion luminescence with modulating emission colors from reddish-yellow towards the greenish area is achieved. The two-photon up-conversion mechanism was also identified by the quadratic dependence between the luminescence intensities and 808 nm excitation source powers. The up-conversion luminescence characteristics indicate that Y 3+ buffers significantly enhance the 2 H 11/2 / 4 S 3/2 → 4 I 15/2 transitions, leading to an approximately five-fold increase in the luminescence intensities ratio R(g/r) of the green to red emissions in Er:SrF 2 phosphors.
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2020
·Vol. 10
·期 3
·355
·
IF 3.52
Wucan Liu,Yongnan Liu,Kabozya M. Mardochee,Zhikun Wang,Shucheng Wang,Wei Yu,Jianjun Zhang,Wenfeng Han
SrF2promotes the dehydrochlorination (DeHCl) of 1,1-difluoro-1-chloroethane, which is the key process for the manufacture of VDF (vinylidene fluoride), one of the most typical fluorinated monomers. However, the selectivity is low as dehydrofluorination (DeHF) to VCF (vinylidene chlorofluoride) competes with the formation of VDF. In this study, SrF2@C (SrF2embedded in carbon) and SrF2@NC (N-doped carbon) catalysts were fabricated following calcination in N2with SrC2O4, PVDF (poly vinylidene fluoride) and urea as the precursors. The catalysts were characterized by XRD, SEM, TEM, and XPS. The results show that both the calcination temperature and N-doping play an important role in the conversion of HCFC-142b and the selectivity to VDF and VCF. Calcination at elevated temperatures enhances the Sr-C interaction. For SrF2@C, improved interaction facilitates withdrawing electrons from Sr by the carbon support. By contrast, the strong interaction of Sr with N-doped carbon supply electrons from N species to Sr. The electron deficiency of Sr is favorable for the adsorption of F with higher electronegativity and consequently, DeHF reaction forming VCF. The supply of electrons to Sr by the support improves the formation of VDF (DeHCl). The present work provides a potential strategy for the improvement of selectivity to the target product.Keywords:dehydrochlorination;dehydrofluorination;metal–support interaction;strontium fluoride;vinyl difluoride
研究领域:
化学工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2025
·
IF 4.2
Zuodong Liu,Qiyue Pan,Chengwei Zhang,Guo Zhang,Rui Liu,Tingting Xiong,Yongsheng Yu,Peng Liu,Qiangshan Jing
Er, Y:SrF 2 particles co-doped with various Y 3+ buffer ions were prepared after calcined as-synthesized particles at 600 °C, and the residual nitrates and –OH disappear drastically after calcination treatment. XRD and FE-SEM measurements were proposed to identify the crystal structures and morphologies of the Er, Y:SrF 2 particles, respectively. The emission spectra illustrated two distinct emission bands, which can be attributed to the 2 H 11/2 / 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions of Er 3+ ions, respectively. The dependence of green to red emission intensity ratio R(g/r) and the decay curves on the Y 3+ buffer ions co-doping contents were investigated to elucidate the emission mechanisms. It was observed that the 2 H 11/2 / 4 S 3/2 → 4 I 15/2 transitions were enhanced relative to 4 F 9/2 → 4 I 15/2 red-emitting transition under 488 nm and 980 nm excitation in high-symmetry Er, Y:SrF 2 particles after co-doped with Y 3+ buffer ions.
✓ 已验证
产品关联
DOI
高影响因子
CHEMOSPHERE
·
2023
·
IF 8.8
Huiqi Zheng,Xiaorong Meng,Jiao Wu,Danghao Liu,Shanshan Huo
Heavy metal pollution can significantly harm water systems and human health. Combining photoelectrocatalytic (PEC) and nanofiltration (NF) membrane separation technologies can effectively remove heavy metal ions from wastewater. In this study, a water bath method was used to form SrF 2 /Ti 3 C 2 T x (ST) nanoparticles on the surface of polyvinylidene fluoride (PVDF) membranes and an additional polyamide (PA) functional layer was formed at the interface by crosslinking. ST@PA composite NF membranes (STPP) with good photocatalytic performance were obtained. The separation and catalytic properties of the STPP membranes were controlled by the ST content, which modifies the surface structure and properties of the membranes. The membrane with optimal ST crosslinking exhibited a water contact angle of 50.8°, pure water flux of 24.6 L·m −2 ·h −1 ·bar −1 , and rejection rates of Mn 2+ , Ni 2+ , Cu 2+ , and Zn 2+ of 98.8%, 95.3%, 95.7%, and 97.3%, respectively, under PEC-assisted separation with visible light illumination from a Xe lamp (300 W) and an applied voltage (2 V). The STPP membranes showed improved rejection rates of heavy metal ions under PEC-assisted operation. The mechanism for the improved membrane performance under PEC conditions was preliminarily clarified considering the relationship between the photocatalytic and filtration properties of STPP membranes along with the influence of light irradiation and an external voltage on the heavy metal ions. The generation of electrons, holes, superoxide radicals, and hydroxyl radicals during membrane operation enhances the rejection rates of heavy metal ions. Based on these results, STPP membranes are considered a promising technology for industrial applications in heavy metal removal.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
OPTICAL MATERIALS
·
2021
·
IF 3.08
Linxuan Wang,Xu Yang,Maohui Yuan,Zining Yang,Kai Han,Hongyan Wang,Xiaojun Xu
In this work, a series of Nd 3+ and Yb 3+ codoped SrF 2 nanocrystals (NCs) were synthesized by the hydrothermal method . The TEM results show that the average size of these NCs is approximately ∼50 nm. The structure of SrF 2 NCs and its optical properties of near-infrared (NIR) downconversion luminescence (DCL) are systematically characterized. Under the excitation of 808 nm laser, intense NIR DCL centered at 976 nm from Yb 3+ ions is experimentally determined. The mechanism of the DCL is further interpreted based on the efficient energy-transfer (ET) processes from Nd 3+ to Yb 3+ . In addition, utilizing the fluorescence intensity ratio (FIR) technique, the temperature sensing behaviors of SrF 2 :Nd 3+ /Yb 3+ (15/4 mol%) are also investigated through the heterogeneously coupled states between Nd 3+ ( 4 F 3/2 → 4 I 11/2 ) and Yb 3+ ( 2 F 5/2 → 2 I 7/2 ) in a temperature range of 298–573 K. The results confirm that the maximum thermal sensitivity is up to 0.00346 K −1 at 473K. The excellent thermal sensitivity of these NCs, particularly the DCL located at the NIR region, have the potential for biological applications and temperature measurement at the nanoscale .
研究领域:
材料科学
·
光学
·
生物医学工程
✓ 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）