JOURNAL OF ALLOYS AND COMPOUNDS
·
2021
·
IF 5.316
Xinwen Liu,Guolong Tan,Zhiwei Zhou,Weiwei Li,Yu Yang,Zaichun Sun,Bingchu Mei
As one of the quickest inorganic scintillators, BaF 2 crystal is projected to be used in medical treatment, high energy physics, geological research, and other sectors. A series of Pr:BaF 2 polycrystalline transparent ceramics with nominal Pr 3+ concentrations (0.1–5 at%) were synthesized via HP sintering in this research. XRD , FE-SEM, and TEM measurements were used to analyze the phase composition and microstructure of BaF 2 precursor powders with varying Pr-doping levels, and the results demonstrated that as concentration increases, the size of the nanopowders decreases. Furthermore, the morphology shifted from uniform square to uneven sheet. Cross-sectional SEM pictures of all samples revealed a clean grain boundary with no remaining pores or contaminants. The absorption spectra , emission spectra, and fluorescence lifetime of a group of Pr:BaF 2 transparent ceramics with excellent optical transmittance were measured and discussed after hot-pressing the precursor powders synthesized via co-precipitation method at 900 °C under an axial pressure of 50 MPa for 4 h.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2021
·
IF 3.599
Dangli Gao,Yuqian Liang,Jie Gao,Hong Xin,Long Wang,Sining Yun,Xiangyu Zhang
Applications of rare-earth (Re)-doped upconversion (UC) micro/nanocrystals in varying areas have sparked a growing, constant demand for deliberate control over the luminescent profile and lifetime. A general strategy for adjusting UC luminescence is to control the dopant Re 3+ concentration. However, the progress of elevating dopant concentration is significantly limited owing to frequently encountering severe concentration quenching. Herein, by designing UC system using Tm 3+ with super long intermediate energy level lifetime and Yb 3+ with a simple two-level structure as a activator/sensitizer combination, we have achieved the unusually intense deep ultraviolet (UV) UC emissions at 290 nm and 345 nm, near UV emission at 361 nm, visible blue emissions at 452 nm and 478 nm, and near infrared (NIR) emission at 803 nm in NaYF 4 :Yb/Tm microtubes under 980 nm excitation. The luminescence intensity reaches about 56 times and 8 times enhancement for the UV and blue emission, respectively, with the increase of dopant Yb 3+ contents from 20 to 80 mol%. While luminescence lifetimes for all emissions decrease, particularly, for NIR emission at 803 nm, from 1507 μs down to 384 μs. Importantly, upon 980 nm irradiation, these UC NaYF 4 :Yb/Tm microtubes exhibit superior optical performance as a promising candidate of advanced anti-counterfeiting applications and other applications including UV light triggered reactions and multiplexing information storage.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
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
OPTICAL MATERIALS
·
2023
·
IF 3.9
Yanbin Wang,Ziqiu Cheng,Junhao Ye,Chen Hu,Zhenzhen Zhou,Yuyang Chen,Haohong Chen,Denis Yu Kosyanov,Jiang Li
Compared to phosphor and phosphor in glass, phosphor ceramics have higher thermal properties , and are less prone to thermal quenching. (Ce,Lu) 3 Al 5 O 12 (Ce:LuAG) has better thermal stability than most of the phosphors, such as (Ce,Y) 3 Al 5 O 12 (Ce:YAG). However, the high melting point of Lu 3 Al 5 O 12 (LuAG; up to 2010 °C) presents a great challenge in producing transparent ceramics (TCs), so a series of Ce:LuAG nanopowders with high sintering activity were prepared by the co-precipitation method and then used as initial materials to obtain x at.% Ce:LuAG ( x = 0.05, 0.1, 0.2, 0.3, 0.35, 0.4, 0.5, 0.55, 0.6, 0.65, 0.7) TCs by vacuum sintering at 1775 °C for 10 h. Moreover, the luminous properties of typical Ce-doped LuAG phosphors were systematically investigated using excitation by light-emitting diodes or laser diodes (LEDs/LDs). The emission intensity of 0.4 at.% Ce doped sample is the highest among all TCs with Ce amount ranging from 0.05 to 0.7 at.% at room temperature. The photoluminescence intensity of 0.4 at.% Ce:LuAG only decreases by 12.5% from 25 to 225 °C. The 0.4 at.% Ce:LuAG based on 0.8 W LEDs and 1.1 W LDs has the optimum luminous flux of 71.5 and 113.7 lm and the luminous efficiency of 89.3 and 101.4 lm∙W −1 , respectively. As Ce concentration increases, a decrease in the luminescence saturation threshold of TCs is observed with a blue laser power density of 2.5–36.9 W∙mm −2 . A high-flux yellow-green light of 1166.9 lm is obtained from 0.1 at.% Ce:LuAG when excited with a high-power LD with an energy density of 36.9 W∙mm −2 . This work explored the best Ce doping level in Ce:LuAG TCs, as well as the luminescence saturation threshold in remote laser lighting applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yee-Shin Chang,Cheng-Xin You,Tai-Chen Kuo
In this study, SrY₂O₄:Dy³⁺ phosphors were synthesized using the solid-state reaction method and evaluated after heat treatment at 1300 °C for 5 h. XRD analysis confirmed the orthorhombic structure of SrY₂O₄ with residual Y₂O₃ present. The addition of Dy³⁺ ions caused lattice expansion, impacting grain size and crystallinity. SEM images showed that the phosphor particles had irregular shapes with minimal size variation, although they tended to agglomerate due to high-temperature heat treatment. Optical analysis revealed significant absorption and emission peaks, with a strong excitation band in the 200–306 nm range and prominent sharp peaks in the 306–480 nm range, particularly at a 0.5 mol% doping concentration. Emission spectra indicated the highest intensity at 0.5 mol% Dy³⁺ concentration, with intensity decreasing due to concentration quenching at higher levels. Thermal stability tests showed peak emission intensity at 70 °C, with stability maintained up to 190 °C before notable thermal quenching. Chromaticity coordinates remained within the warm white region at both temperatures. This study provides detailed insights into the effects of Dy³⁺ doping on the structural, optical, and thermal properties of SrY₂O₄ phosphors. Compared to previous studies on rare-earth-doped SrY₂O₄ phosphors, this work is the first to systematically explore the substitution of Y³⁺ ions with Dy³⁺ ions until full replacement. The study not only confirmed that the highest emission intensity occurs at 0.5 mol% Dy³⁺ concentration, but also demonstrated that Dy³⁺-doped SrY₂O₄ phosphors exhibit excellent thermal stability, with emission stability maintained below 150 °C. These findings expand the potential applications of Dy³⁺-doped SrY₂O₄ phosphors, particularly in high-temperature environments and solid-state lighting.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2020
·
IF 3.104
Reziwanguli Yantake,Aierken Sidike,Taximaiti Yusufu
This study presents the photoluminescence characteristic analysis of a series of red phosphors of KAlSiO 4 :1.5 mol%Sm 3+ , x mol%Eu 3+ ( x = 2, 3, 4, 5, 6, 7) prepared via high-temperature solid-phase reaction. The results show that the X-ray diffraction (XRD) refinement results are reliable. The unit cell parameters and volume gradually decrease as the Eu 3+ concentration increases, resulting in a grain size reduction of 10.22%. When x = 6, the emission peaks of Sm 3+ at 564, 601, and 651 nm disappear completely, and the corresponding full width at half maximum becomes 0. At 610 nm, the emission peak intensity of Eu 3+ is increased by a factor of 4.8. The resonant non-radiative energy transfer effect is greater than the co-excitation effect. A maximum energy transfer efficiency of 97.8% is achieved. The integral area at 610 nm is as high as 85%. The color purity of the phosphor is as high as 92.97%, and the internal quantum yield gradually changes from 32% to 51%. Ultimately, these results confirm that the silicate phosphor is suitable for the red component in the three primary color phosphors of white light-emitting diodes.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Hanzhi Yao,Yuchi Zhang,Yan Xu
Self-calibrated optical luminescent thermometers were prepared based on Eu 3+ /Mn 2+ co-doped Zn 2 GeO 4 phosphors with controllable morphology via a facile hydrothermal synthesis process. The co-doped concentration of Eu 3+ ions in Zn 2 GeO 4 :Mn 2+ played important roles in the evolution of the morphology and the formation of the dual luminescent emission mode. Depending on different excitation wavelengths ranging from 260 to 360 nm, the dual emission centers located at about 534 nm and 612 nm were ascribed to d - d transition derived from 4 T 1 - 6 A 1 of Mn 2+ ions and f - f transition originated from 5 D 0 - 7 F 2 of Eu 3+ ions, respectively, which gave rise to the excellent self-calibrating temperature sensing functions. The related luminescent and sensing mechanism of the Eu 3+ /Mn 2+ co-doped Zn 2 GeO 4 phosphors are also proposed. The as-obtained Eu 3+ /Mn 2+ co-doped Zn 2 GeO 4 phosphors had a high relative sensitivity ( S r ) of 1.96% ºC −1 between 20 and 80 °C, as well as stable reusability, demonstrating its superiority as a ratiometric luminescent thermometer for temperature sensing applications.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMISTRY OF MATERIALS
·
2019
·
IF 10.159
Yuanyuan Ma,Jianbi Xia,Chenyang Yao,Fang Yang,Stefan G. Stanciu,Peng Li,Yinhua Jin,Tianxiang Chen,Jianjun Zheng,Guoping Chen,Hongxin Yang,Liqiang Luo,Aiguo Wu
Given that the contrast of Zn-doped Fe3O4 nanoparticles (NPs) (ZnxFe3–xO4) in magnetic resonance imaging (MRI) depends on their intrinsic chemical and physical properties such as doping content or size, the ability to finely control these characteristics is very important but at the same time very challenging. In this work, we introduce a novel doping mechanism and present how various desired MRI contrast levels can be precisely achieved by synthesizing ZnxFe3–xO4 nanoparticles in a controlled and reproducible manner, exhibiting different Zn doping concentrations (ZnxFe3–xO4, x = 0/0.1/0.2/0.3/0.4) and different dimensions (4/7/10 nm). The experimental results show that ZnxFe3–xO4 NPs of a specific dimension form a system whose saturation magnetization and crystal structures can be easily tuned by adjusting their Zn doping contents. The proposed model thus enables the exact tuning of MRI contrast by controlling NP doping content and size. The utility of our study is not restricted to the case of the considered material, as it can be easily extrapolated and applied in the case of other divalent transition metal ion-doped magnetic NPs, to optimize their MRI contrast and eventually other relevant properties for further biomedical applications.
研究领域:
材料科学
·
医学影像
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xinxin Wang,Zhihua Long,Wei Qian,Yunxia Ye,Fengze Dai,Yinqun Hua,Jie Cai
Tremendous efforts have been devoted to exploring alternative materials to 8 wt% yttria-stabilized zirconia used for thermal barrier coatings . In this work, novel composite ceramic GdPO 4 /GdTaO 4 was designed by introducing GdTaO 4 as second reinforcement phase into GdPO 4 matrix. Mechanical and thermophysical properties of resulting composites were studied as a function of doping concentration of GdTaO 4 . Results suggested GdPO 4 /GdTaO 4 composite ceramics consisting of GdPO 4 monazite and GdTaO 4 monoclinic phases, indicating GdPO 4 and GdTaO 4 with maintained excellent chemical compatibility at high temperatures. GdPO 4 /GdTaO 4 composite ceramics achieved superior hardness of 5.82 GPa, fracture toughness of 2.72 MPa m 1/2 , and thermal conductivity of 1.36 W•m −1 •k −1 at GT doping concentration of 50 wt% owing to grain refinement and scattering of phonons caused by the doped GdTaO 4 phase. In sum, excellent mechanical and thermophysical properties of GdPO 4 /GdTaO 4 composite ceramics look potential for thermal barrier coatings materials.
研究领域:
材料科学
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
ACS Photonics
·
2017
·
IF 6.756
Yue Yang,Yingbin Zhu,Jiajia Zhou,Fan Wang,Jianrong Qiu
The growing applications of upconversion nanocrystals in bioimaging, therapeutics, and photonics have given rise to a demand of high quality nanocrystals with desirable luminescence intensity. Although the design of optimal nanocrystals such as core–shell nanostructures has improved the intensity, the internal links between dopant concentration balance, epitaxial growth protection, and shell thickness effect encounter a compromised situation that lacks of integrated consideration and comprehensive assessment. Here we propose an integrated strategy based on a core–shell design for the enhancement of upconversion luminescence intensity. Epitaxial protection can enable higher activator accommodation capacity in limited spatial scale, which leads to an Er3+ concentration threshold improvement in β-NaYF4 core–shell nanocrystals from 2 to 6 mol %. We further perform a comprehensive assessment of the nanocrystals with convincing performance improvement in ensemble spectroscopic intensity, upconversion quantum yield, and single nanocrystal intensity. Our findings provide improved understanding of electronic behaviors in multiphoton upconversion and opportunities for diverse applications requiring high quality upconversion nanocrystals.
研究领域:
生物成像
·
纳米材料科学
·
光子学
✓ 已验证
DOI
高影响因子
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
·
2023
·Vol. 33
·期 7
·075007
·
IF 2.3
Jianqiang Han,Weihua Sun
Front-side releasing suspended structures made using bulk micromachining processes have the advantages of simplifying vacuum or hermetic packaging processes and reducing squeeze-film damping. This paper studies the effect of doping concentration on the etching rate (ER) of the (111) plane. The experimental results show that increasing the boron doping concentration (but to less than the self-stop etching concentration) significantly increases the ER of the (111) plane and the ER ratio of the (111) and (100) planes. This phenomenon is used to speed up the undercutting and release <110> oriented clamped–clamped beams, which can be used as piezoresistive sensitive elements. The etching depth when the microbeams have just been released and the silicon wedges under single beams, double beams and triple beams disappear is deduced and verified by experiments. This has a certain guiding significance for designing piezoresistive sensors.
研究领域:
微机电系统
·
半导体工艺
·
传感器技术
✓ 已验证
DOI
高影响因子
Nature Communications
·
2025
·Vol. 16
·期 1
·1-12
·
IF 15.7
Xu Junling,Xie Fuqiang,Huang Lipeng,Li Nana,Peng Shang,Ma Wensheng,Zhang Kai,Wu Yanxue,Shao Lianyi,Shi Xiaoyan,Chen Jizhang,Tao Li,Zhang Kai,Zhang Zhonghua,Wang Yonggang,Sun Zhipeng
Doping is an important approach to tailor materials’ properties, yet the success of doping can depend on factors such as ionic radii similarities. For materials like silicon or perovskite, doping is not only facile to implement but can also enhance material properties. However, for host lattice structures like Nb 2 O 5 , doping without causing phase change is challenging. Here, we introduce a high-entropy-doping effect in Nb 2 O 5 . Unlike traditional doping approaches, high-entropy-doping minimizes the chemical properties of doping elements and focuses solely on their quantities. By high-entropizing the doping elements (selecting 10–15 from Mg, Ca, Sr, Ba, Cr, Mn, Fe, Co, Ni, Cu, Zn, Al, Ga, In, Sn, Sb, Y, Mo, La, Ce) and keeping them within a certain range of doping concentrations (1–3 mol %), a successful high-entropy-doping is achieved for Nb 2 O 5 without phase change. The obtained high-entropy-doped (HED) Nb 2 O 5 exhibits rapid-charging capabilities. At a rate of 40 A g −1 , the HED-Nb 2 O 5 delivers a capacity of 80 mAh g −1 , whereas the undoped Nb 2 O 5 fails to exceed 25 mAh g −1 .
✓ 已验证
产品关联
DOI
PubMed
高影响因子
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