OPTICAL MATERIALS
·
2017
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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
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光学工程
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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
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光学工程
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DOI
高影响因子
INORGANIC CHEMISTRY COMMUNICATIONS
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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.
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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
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Longfei Zhang,Ruite Liu,Zaiyang Wang,Feng Guan,Yanchao Li,Xinqiang Yuan,Long Zhang,Yiguang Jiang
Er 3+ -doped transparent perfluoride composite glass (PFCG) containing SrF 2 crystals was obtained by a one-step method. PFCG was observed to maintain the formation of a single SrF 2 crystal phase even when the Er 3+ doping concentration was as high as 8 mol%. Importantly, Er 3+ was enriched in the crystalline region, which promoted grain growth. This ensures effective emission of upconversion (UC). Interestingly, green and red UC emissions were found to be tunable in the range of 1–6 mol% Er 3+ doping, and the UC emission and lifetime started to produce concentration quenching until 6 mol% Er 3+ doping. To the best of our knowledge, this is the highest quenching concentration of Er 3+ in composite-glass materials. Moreover, the dominant UC process was systematically analyzed at different doping levels. This research is expected to provide ideal candidate materials and appropriate Er 3+ concentration doping level guidance in PFCG for the field of UC lasers.
研究领域:
材料科学
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光学
·
光子学
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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.
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高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2025
·
IF 3.5
Yanli Zhang,Jiale Zhao,Simeng Zeng,Zixuan Liu,Bo Wang,Fuhua Lin
In this paper, a novel Cu/F co-doping strategy is proposed to modify the electrochemical performance of Sr 2 Fe 1.5 Mo 0.5 O 6– δ (SFM) cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The pristine SFM, Cu-doped Sr 2 Fe 1.4 Cu 0.1 Mo 0.5 O 6− δ (SFCM) and Cu/F co-doped Sr 2 Fe 1.4 Cu 0.1 Mo 0.5 O 5.9− δ F 0.1 (SFCMF) powders were synthesized by acid-glycine combustion method, and the impacts of Cu/F co-doping on the performance of SFM cathode were investigated systematically. It's found that Cu-doped SFCM has higher oxygen vacancy content and electrical conductivity than the pristine SFM and Cu/F co-doped SFCMF cathodes. While the Coulombic force between B-sites metallic ions and oxygen ions are significantly weaken for SFCMF, enhancing the mobility of lattice oxygen. Due to the combined effects of Cu and F doping, SFCMF cathode exhibits the best electrochemical performance among all investigated samples. At 600 °C, the polarization resistant for SFCMF cathode is 1.79 Ω cm 2 , decreased by 43.71 % in contrast to the parent SFM cathode. These results indicate that Cu/F co-doping is an effective strategy to improve the electrochemical properties of perovskite cathode materials.
研究领域:
能源材料
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电化学
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燃料电池
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材料科学
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无机化学
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DOI
高影响因子
JOURNAL OF POWER SOURCES
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2025
·
IF 7.9
Minglu Wang,Yun Da,Meiqiu Xie,Zheng Wang
Solid oxide electrolysis cell (SOEC) is recognized as a promising and efficient energy conversion technology by converting CO 2 into CO for achieving carbon neutrality. However, the cathode materials with insufficient electrocatalytic activity and stability greatly limit its large-scale commercial application. Herein, a synergistic strategy of high-entropy engineering and anion doping is proposed to develop a novel highly efficient and stable cathode material for CO 2 electrolysis in SOEC. Fluorine doped high-entropy perovskite La 0.6 Sr 0.4 Fe 0.3 Co 0.2 Ni 0.2 Mn 0.2 Mo 0.1 O 3-δ (LSFCNMM-F) is successfully synthesized to boost the CO 2 electrolysis performance. F doping can weaken the strength of metal-oxygen bond, increasing the concentration of oxygen vacancies, which significantly promotes the CO 2 adsorption and activation. Accordingly, F-doped high-entropy perovskite LSFCNMM-F cathode exhibits outstanding electrochemical performance and excellent stability for CO 2 electrolysis in SOEC. Compared to the pure high-entropy perovskite LSFCNMM, F-doped high-entropy perovskite LSFCNMM-F achieves 24.5 % improvement in current density with a remarkable value of 1.78 A/cm 2 at 1.5 V and 800 °C, surpassing most of the reported cathode materials in SOEC field. Moreover, the single cell with LSFCNMM-F cathode exhibits better long-term stability than that with pure high-entropy perovskite LSFCNMM cathode during 100 h operation at 1.2 V and 750 °C, owing to the inhabitation of Sr segregation on the electrode surface after F doping. The results from this study provide insights into the role of synergistic strategy for combining high-entropy engineering and anion doping in developing highly efficient and stable cathode for CO 2 electrolysis using SOEC technology.
研究领域:
材料科学
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能源技术
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化学工程
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DOI
高影响因子
Laser & Photonics Reviews
·
2024
·
IF 9.8
Ying Li,Shuangqiang Fang,Qiangqiang Zhu,Shuxing Li,Bo Liu,Fu Feng,Rongjun Xie,Le Wang
Sunlight like optical source is the primary objective of healthy lighting. In contrast, achieving full spectrum lighting with high stability remains challenging, mostly due to the scarcity of purple chip-pumped cyan-green phosphors and their inherent emission instability. In this study, a novel strategy is presented that realizes simultaneous enhancements in both humidity stability (increased by 2.9 times) and luminescence quantum efficiency (enhanced by 1.5 times) for cyan-emitting Sr 3 AlO 4 F:Ce 3+ phosphor by employing Si/N doping. Theoretical modelling shows that these improvements are attributed to the regulation of energy bands and structural rigidity as well as modulation of the ionicity of chemical bonds. Furthermore, blending the other violet chip-pumped phosphors, sun-like LEDs that accurately replicate solar spectra in different times of the day with an optimal color rendering index of 99 is successfully engineered. Moreover, the universality of this strategy on other oxyfluoride phosphors has also been validated. This groundbreaking outcome offers a practical solution to overcome the inherent luminescence stability limitations in oxyfluoride phosphors, thus catalyzing the application of these cyan-green candidates in sun-like LED lighting.
研究领域:
材料科学
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光学工程
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DOI
高影响因子
Laser & Photonics Reviews
·
2025
·Vol. 19
·期 16
·2500221
·
IF 10
Jingxuan Zhang,Hengwei Lin,Jiaren Du
Photochromic materials have shown significant potential in a plethora of possible applications. However, in practical applications, they remain limited by intricate multi-stage synthesis processes and a restricted range of photochromic colors. Modulating the chromatic properties involves an intricate manipulation of their chemical composition, crystal structure, and trapping energy levels, rendering it extremely challenging to achieve a desired color gamut. In this study, apatite-type materials are rapidly synthesized using a microwave-assisted approach. The photochromic behavior is systematically examined by substituting F⁻ ions with Cl⁻ ions, facilitating the transformation of color centers from pink to green and ultimately to blue. Notably, the prominent reflectance absorption peak ≈554 nm exhibited a gradual red shift to 625 nm. A thorough characterization reveals that this large shift in wavelength of F-center arises from the effective modulation in the trapping energy levels with differing trap distributions linked to photochromism observed across the various Sr₅(PO₄)₃F₁₋ x Cl x :1%Eu. Finally, the potential applications of these multicolor compounds are demonstrated in routine chromatic decorations and sophisticated multi-hued cryptographic technologies. These findings highlight the efficacy of trapping energy management in optimizing photochromic behavior and the considerable capability of the photochromic materials for on-demand practical applications.
研究领域:
材料科学
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光功能材料
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固态化学
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纳米光学
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信息加密技术
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产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2024
·
IF 3.8
Xiaoman Li,Xinyu Liu,Pengfei Zhai,Ruijin Fan,Rongfei Wei,Hai Guo
The demand for white-light luminescent materials for the white-light-emitting diodes (W-LEDs) field has been growing in modern life. In this work, a series of Sn 2+ and Mn 2+ ions co-doped highly transparent white-light emitting oxyfluoride glasses (precursor glass, PG) and Sr 2 LuF 7 glass-ceramics (GC) were successfully prepared by the melt-quenching technique. Their luminescent and structural properties were investigated by the transmission spectra, excitation and emission spectra at different temperatures (300-500 K), luminescent decay curves, XRD, and TEM characterizations. Upon excitation with ultraviolet (UV) light, tunable broadband blue-white light emissions of Sn 2+ were obtained by adjusting the concentration of Sn 2+ ions. A conspicuous energy transfer process from Sn 2+ to Mn 2+ was observed in Sn 2+ /Mn 2+ co-doped samples. Tunable broadband luminescence between blue-white light and orange-red light regions and nearly pink-white light emission was realized by varying Mn 2+ concentration. Furthermore, compared to PG samples, the emissions were enhanced in GC samples due to the crystallization of Sr 2 LuF 7 nanocrystals. Excellent thermal stability was also performed in these Sn 2+ doped PG and GC samples with a recovering value of 96 % and 98.8 %, respectively. Simultaneously, Sn 2+ doped PG and GC samples also own good optical thermal sensitivities with an S A value of 2.28 % and 2.47 % K - 1 , respectively. Our results indicate that these Sn 2+ /Mn 2+ co-doped PG and GC may serve as tunable light sources under UV excitation and have prospects on the ratiometric optical thermometry fields.
研究领域:
材料科学
·
光学工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Mo Wei,Juan Liu,Bing Liu,Kai Xin Song,Cheng Chao Hu,Yu Hui Huang
Alkaline earth metal fluorides, BaF 2 and SrF 2 , are promising low-permittivity ceramics with excellent microwave dielectric properties. However, achieving ideal densifications in BaF 2 and SrF 2 ceramics remains challenging due to their low surface-free energy. In this study, the sintering characteristics of BaF 2 and SrF 2 ceramics are optimized via forming (1– x )BaF 2 - x SrF 2 ( x = 0.2, 0.4, 0.5, 0.6, and 0.8) solid solution ceramics. X-ray diffraction (XRD) patterns and Raman spectra provide compelling evidence for successfully forming (1– x )BaF 2 - x SrF 2 solid solutions across the entire composition range. The solid-solution effect significantly enhances densification at a much lower sintering temperature of around 825 °C. Notably, 0.6BaF 2 -0.4SrF 2 ceramics exhibit the optimal microwave dielectric properties with a permittivity ( ε r ) of 7.26, quality factors ( Qf ) of 61,006 GHz at 10 GHz and 106,000 GHz at 25 GHz, and a temperature coefficient of resonant frequency ( τ f ) of −97.46 ppm/ ° C. Additionally, the advancement of low-temperature co-fired ceramic (LTCC) technology for high-density electronic packaging presents a significant challenge in achieving compatibility between the coefficient of thermal expansion (CTE) of the packaged components. The 0.6BaF 2 -0.4SrF 2 ceramics exhibit a significantly higher CTE of 21.67 ppm/ ° C compared to most low- ε r ceramics (usually below 10 ppm/ ° C), resulting in better CTE matching with organic laminates and metal electrodes. Therefore, BaF 2 -SrF 2 solid solution ceramics, addressing the need for low- ε r , high- Qf , and high CTE, offer a potential solution for high-reliability LTCC electronics.
研究领域:
材料科学
·
电子工程
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DOI
高影响因子
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