MATERIALS RESEARCH BULLETIN
·
2023
·
IF 5.4
Miao Gao,Baosheng Cao,Zhichao Liao,Lulu Qiu,Yangyang He,Bin Dong
This paper explores the detailed photoluminescence (PL) behaviors of Dy 3+ doped CaWO 4 (Dy:CaWO 4 ) phosphors under multi-ultraviolet wavelength excitation. Moreover, it proposes multi-strategy ratiometric thermometry based on luminescence intensity ratio (LIR) from the transitions of thermally coupled energy levels (TCLs) of Dy 3+ . Under excitation of multiple ultraviolet wavelengths, the Dy:CaWO 4 phosphors exhibited multi-wavelength responsive PL characteristics of Dy 3+ with strong blue and yellow emissions from Dy 3+ TCLs transitions. The temperature-dependent PL properties of Dy:CaWO 4 phosphors were investigated over a temperature range of 300∼650 K. Multi-strategy ratiometric luminescent thermometry was examined under various excitation wavelengths by the thermal equilibrium population of Dy 3+ TCLs. The proposed six LIR schemes based on the PL emissions of Dy 3+ exhibited a good quantitative relationship with temperature. They showed well-luminescent thermometric behaviors with high absolute and relative sensitivities due to the largest energy gap of TCLs and a relatively larger LIR value. The thermometry properties of the multiple LIR schemes were independent of excitation wavelength, attributed to the stable site symmetry of Dy 3+ and the thermal equilibrium population of TCLs under different excitation wavelengths. The multi-strategy ratiometric thermometry of Dy 3+ demonstrated the merit of high sensitivity, excellent stability , and repeatability, indicating the potential luminescent thermometric application of Dy:CaWO 4 phosphors.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2026
·Vol. 46
·期 12
·118409
·
IF 6.3
Qiulei Li,Siqi Zou,Alberto José Fernández-Carrión,Jiazheng Hao,Lunhua He,Xiaojun Kuang,Xiaoyan Yang
This work investigates the effect of rare-earth substitution on the structural, electrical and microwave dielectric properties of scheelite-type CaWO 4 ceramics. Ca 0.98 RE 0.02 WO 4+ δ ( RE = La–Yb) samples were prepared and uniformly sintered at 1150 °C. Ca 0.98 Yb 0.02 WO 4+ δ exhibits the highest ε r and Q × f values (ε r ∼10.62, Q × f ∼ 65,868 GHz), albeit with a negative τ f (-56.7 ppm/°C). In contrast, bulk conductivity varies non-monotonically with ionic radius and reaches a local maximum near A-site dopant/host radius matching, consistent with a lower migration barrier. Structural analysis indicates that nominal A-site cation radius mismatch modifies local bonding and lattice dynamics, leading to different responses in bulk transport and microwave dielectric behavior. These results establish a clear radius-dependent structure–property relationship in dilute RE -doped CaWO 4 and identify nominal A-site cation radius mismatch as an effective compositional parameter for balancing transport and microwave dielectric performance.
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CERAMICS INTERNATIONAL
·
2026
·
IF 6
Hengji He,Dainan Zhang,Youbin Zheng,Shuyang Ma,Cheng Liu,Qinghui Yang,Huaiwu Zhang
This study modified CaWO 4 ceramics through co-doping with Li + and Mo 6+ , and prepared Li x Ca 1-x W 1-x Mo x O 4 (x = 0–0.10) using the solid-state reaction method. The results show that at x = 0.02 and sintered at 850 °C, the material exhibits optimal comprehensive performance: ε r ≈ 9.95, Q × f = 79,683 GHz, and τ f improved from −53 to +5.08 ppm/°C, achieving low-temperature sintering and effective temperature stability control. Mechanism analysis indicates that the enhancement of Mo–O bonds and charge transfer behavior contribute to reducing dielectric loss and improving temperature stability. The material also demonstrates good dielectric performance in the terahertz frequency band. A patch antenna designed based on this material achieves a radiation efficiency of 91.47% at 11.65 GHz, highlighting its potential for application in high-frequency LTCC devices.
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CHEMISTRY OF MATERIALS
·
2026
·Vol. 38
·期 17
·8816-8828
·
IF 7.1
Jiang Xinyu,Li Qiulei,Fernández-Carrión Alberto J.,Kuang Xiaojun,Yang Xiaoyan
Alkali-metal ion substitution has emerged as a promising
strategy
for engineering advanced solid-state ionic conductors. In this work,
a series of A-site-substituted CaWO 4 ceramics (A = Na,
K, Cs; 5% nominal substitution) was synthesized via solid-state reaction.
A systematic investigation of phase formation, structural stability,
and electrical properties reveals that partial substitution of Ca 2+ by alkali ions enhances the total conductivity by one to
2 orders of magnitude. Quantitative transference-number analysis demonstrates
that charge transport at 800 ° C is dominated by alkali-cation
migration in the Na- and K-substituted samples, with estimated cationic
contributions of approximately 87% and 83%, respectively, whereas
the Cs-substituted sample exhibits comparable cationic and electronic
contribution. Comparative defect-energy calculations indicate that
Na-related interstitial configurations are energetically more accessible
than the corresponding K- and Cs-related configurations among the
examined models. AIMD simulations further visualize a continuous Na + hopping pathway through the available interstitial space
of the scheelite framework. These results suggest that alkali-cation
migration, rather than oxygen-vacancy migration, is primarily responsible
for the enhanced conductivity in Na- and K-substituted CaWO 4 . These results indicate the size-dependent regulation of charge
carriers in alkali-metal-substituted CaWO 4 and provide
mechanistic insights for the rational design of tungstate-based mixed
ion–electron conductors.
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Materials Chemistry Frontiers
·
2025
·
IF 6.4
Terefe Tafese Bezuneh,Xin Li,Tongtong Kou,Fuchun Nan,Zilong Wu,Lanbo Shen,Xinyuan Xia,Bin Li,Liang Wang,William W. Yu
Calcium tungstate nanocrystals CaWO4 NCs represent an important family of inorganic oxides and are well-known for their rare-earth (RE) sensitizing properties. Although RE-doped CaWO4 NCs have been extensively used in the optical field, their applications as a fluorescent probe is yet to be explored. In this report, inspired by their excellent luminescence properties, we demonstrate the potential of terbium-activated CaWO4 NCs as a fluorescent probe for sensing and biological imaging applications. In our study, we successfully synthesized nano-sized water dispersible PEG coated Tb–CaWO4 NCs via a facile one-step hydrothermal route. Next, the potential of PEG–Tb–CaWO4 NCs as a fluorescent sensing probe was evaluated by employing a “signal-off–on” sensing strategy for the detection of a key disease biomarker (alkaline phosphatase, ALP). The proposed detection system realized sensitive detection of ALP with a low limit of detection of 0.5 U L−1. Moreover, the cell imaging potential of PEG–Tb–CaWO4 NCs was investigated using HeLa cells. PEG–Tb–CaWO4 NCs were internalized by HeLa cells through endocytosis and showed characteristic bright green emission, demonstrating the cell imaging potential of the as-synthesized NCs. Also, the viability study confirmed the very low cell cytotoxicity of PEG–Tb–CaWO4 NCs to HeLa cells. Overall, we highlighted the potential of PEG–Tb–CaWO4 NCs as a promising fluorescence probe for sensing and biological imaging applications.
研究领域:
材料科学
·
生物医学工程
·
分析化学
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JOURNAL OF LUMINESCENCE
·
2019
·
IF 2.961
Wei Xu,Yuwei Hu,Longjiang Zheng,Zhiguo Zhang,Wenwu Cao,Hailong Liu,Xijun Wu
Rare earth ions doped luminescent materials have demonstrated their potentiality as sensitive thermometers with good accuracy and high spatial resolution. Nevertheless, low luminescence efficiency, especially at high temperature, still limits the development of this thermometry technique. Here, Nd 3+ /Yb 3+ codoped CaWO 4 phosphors were synthesized using high temperature solid-state method, and Li + ions were introduced aiming to improve the near-infrared (NIR) emissions from Nd 3+ in the spectral range of 725–950 nm. The influence of Li + codoping on the structure and NIR luminescence in CaWO 4 : Nd 3+ /Yb 3+ when excited by a 980 nm laser diode was investigated. NIR-NIR emissions from Li + codoped samples are successfully strengthened compared with that without Li + ions, which is mainly attributed to the distortion of the crystal structure and the increase of crystalline size by Li + . The optical temperature sensing behavior of NIR luminescence from Nd 3+ was studied based on fluorescence intensity ratio (FIR). Assisted by Li + ions, the NIR-NIR emissions are observed to be effectively enhanced with the increment of temperature. And a new pair of thermally coupled levels in Nd 3+ ions with excellent thermometry characteristics is explored, through which superior measurement sensitivity as well as accuracy could be achieved. In addition, light-induced temperature rise was realized in the phosphors, which makes CaWO 4 : Nd 3+ /Yb 3+ /Li + excellent candidate for luminescence thermometry and optical heaters.
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高影响因子
TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
·
2026
·Vol. 36
·期 4
·1245-1257
·
IF 5.5
Rui-heng XIANG,Jie LI,Huai-cheng XIANG,Ying TANG,Di ZHOU,Dou ZHANG,Liang FANG
To modify the near-zero temperature coefficient of resonant frequency ( τ f ) of CaWO 4 -based materials and explore their structure–property relationships, Ca 1− x Nd x W 1− x Nb x O 4 (CWNN x ) ceramics were prepared. Phase evolution occurred in the system from tetragonal-scheelite to monoclinic-fergusonite at x =0.7. Relative permittivity ( ε r ) increased from 11.28 to 16.84, influenced by the polarizability per unit molar volume ( α / V m ), whereas the negative deviations between ε r,corr and ε r,C−M (Δ ε r ≈ −3.39% to −12.50%) resulted from the compression effect of Ca 2+ and Nd 3+ coupled with Nb 5+ at the B site. The quality factor ( Q ) rose by 52%, attributed to the decreased Raman full width at half-maximum and increased lattice energy ( U ). The τ f values changed from −27.6×10 −6 to 72.1×10 −6 °C −1 , governed by the increased temperature coefficient of ionic polarizability ( τ αm ), decreased coefficient of thermal expansion ( α L ), and weakened A-site compression. CWNN0.3 ceramic demonstrated superior properties ( ε r =13.00, Q × f =60170 GHz, and τ f =−1.9×10 −6 °C −1 ), suggesting potential applications in sub-6 GHz antennas.
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CERAMICS INTERNATIONAL
·
2025
·Vol. 51
·期 23
·40683-40691
·
IF 5.6
Baosheng Cao,Qianrui Liu,Lulu Qiu,Yujie Weng,Yangyang He,Xiaoguang Han,Bin Dong
Dy 3+ -doped luminescent materials have a promising application in various optical and optoelectronic fields. The unveiling of detailed energy level distribution and subtle emission transition of Dy 3+ in oxide matrices is vital for developing new optical sensors . In this study, the crystallographic site symmetry of Dy 3+ in CaWO 4 :Dy 3+ phosphors prepared via the co-precipitation method was identified by the XRD , FT-IR, and Raman spectroscopy . The spectroscopic site of the S 4 symmetry of Dy 3+ in CaWO 4 crystals was confirmed using Eu 3+ as the structural probe through high-resolution, low-temperature photoluminescence spectroscopy. The detailed crystal-filed (CF) energy level arrangement and corresponding emission transition lines of Dy 3+ were revealed through the spectral well-resolving and temperature-dependent PL spectra . Furthermore, a new ratiometric thermometric strategy based on the two opposite thermal-dependent CF transitions exhibited excellent sensitivity to a wide temperature range from 80 to 700 K. In addition, a novel barcode anti-counterfeiting applicability has been certified to realize dynamic information encryption . This study provides insight into the development of new Dy 3+ -based phosphors and the exploration of CaWO 4 :Dy 3+ phosphors in advanced luminescent thermometers and anti-counterfeiting under extreme temperature conditions.
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Wei Xu,Ying Cui,Yuwei Hu,Longjiang Zheng,Zhiguo Zhang,Wenwu Cao
CaWO 4 phosphors doping with different Er 3+ and Yb 3+ ion concentrations were synthetized through high temperature solid-state reaction technique. Excited by 980 nm laser, the influence of rare earth dopant concentration on the thermometry behavior of Er 3+ green upconversion emissions was discussed via the fluorescence intensity ratio method. Superior temperature sensing ability could be achieved in CaWO 4 : 0.1 mol% Er 3+ -3 mol% Yb 3+ , the maximum sensitivity of which is about 1.05 × 10 −2 K −1 at 439 K. Meanwhile, the pumping laser induced thermal effect on the saturation of upconversion emission intensity has been preliminarily studied. The temperature of the irradiation spot on sample caused by the exposure of excitation laser is observed to be greatly enhanced as the pumping power increased. Based on the steady-state rate equations and the temperature dependence of luminescence decay curves, theoretical calculations have been performed. The results confirm that the laser induced heating effect plays an important role in the luminescence intensity saturation phenomenon.
研究领域:
光学材料
·
光子学
·
传感器与传感技术
·
发光光谱学
·
固态物理
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高影响因子
JOURNAL OF ANALYTICAL ATOMIC SPECTROMETRY
·
2020
·Vol. 35
·期 5
·886-895
·
IF 3.498
Yuqiu Ke,Jianzong Zhou,Xiaoqing Yi,Yijian Sun,Jianfeng Shao,Shiyong You,Wei Wang,Yunzhi Tang,Chaoyang Tu
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has been widely used for in situ microanalysis of elemental concentrations in solid samples, but its application is hampered by a lack of matrix-matched and homogeneous reference materials (RMs). In this work, a new method for preparing matrix-matched and homogeneous LA-ICP-MS reference materials has been developed. A multiple rare earth element (REE) doped CaWO4 single crystal (CaW-1) was successfully prepared by the Czochralski technique. The matrix composition and crystal structure were confirmed by X-ray diffraction (XRD) and electron microprobe analysis (EMPA), which indicates that these crystals have a matrix composition of CaWO4 and are matrix-matched with natural scheelite. The homogeneity of REE distribution was systematically studied by seven methods and the results demonstrated that REEs are distributed homogeneously in the CaWO4 single crystal with slight fluctuation (RSDs: ca. 4%). It can be concluded that the synthesized CaWO4 single crystal meets both crucial requirements, matrix-matched and homogeneous distribution, for an LA-ICP-MS reference material, and therefore it was used to quantitatively calibrate REE concentrations in natural scheelite. The results showed that acceptable analytical errors (<8%) were obtained, which were more desirable than those obtained with non-matrix-matched NIST SRM 610 as the RM. It robustly validates the ability of the developed method for preparing CaWO4 single crystals as possible LA-ICP-MS reference materials to calibrate REE concentrations in natural scheelite.
研究领域:
矿物学
·
分析化学
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高影响因子
Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 33
·12854-12861
·
IF 5.7
Qianrui Liu,Baosheng Cao,Miao Gao,Lulu Qiu,Yujie Weng,Yangyang He,Xiaoguang Han,Bin Dong
Investigating excitation transition behavior is crucial for elucidating the photoluminescence (PL) characteristics of lanthanide ion-doped phosphors. This investigation provides a basis for developing new ratiometric luminescent thermometry methods based on thermally influenced excitation processes. In this study, the excitation transition lines of trivalent dysprosium (Dy3+) and charger-transfer band (CTB) in Dy3+-doped CaWO4 (CaWO4:Dy) phosphors were effectively deconstructed using the Dy3+ concentration- and temperature-dependent PL excitation (PLE) spectra in the ultraviolet range of 280–340 nm. The phosphors exhibited a thermal-quenched PLE intensity for Dy3+ and a thermal-enhanced PLE intensity for CTB owing to energy transfer between the CaWO4 host and Dy3+. A new ratiometric thermometry strategy was introduced using the opposite thermal-dependent PLE intensity of CTB as the temperature probe and Dy3+ as the reference signal. This method was based on the excited-state absorption intensity ratio between CTB and Dy3+. This new thermometry method exhibited ultra-high performance, reaching maximum absolute and relative sensitivities of 1.72 K−1 at 575 K and 4.66% K−1 at 300 K, respectively. This study presents a novel approach for developing highly sensitive and stable optical thermometric Dy3+-based materials and provides guidance for constructing an effective ratiometric thermometry strategy based on the deconstructed PLE properties.
研究领域:
材料科学
·
光学传感
·
发光测温
·
光子学
·
稀土掺杂材料
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高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Zihan Zhao,Xiuping Wu,Yanjie Zhang,Jiaheng Zhao,Bing Li,Hao Song,Desheng Li
As an all-inorganic solid state lighting material, phosphor-in-glass (PiG) receives much attention in high-power white lighting. However, poor heat-dissipation performance and low color rendering index (Ra) caused by low doping concentration of phosphor limit its application in white laser diodes (wLDs). Herein, phosphor-in-glass films on sapphire (PiFS) with heat-conducting properties and high Ra were newly synthesized via screen printing technology, which is highly desired for high-power wLEDs/wLDs. The interfacial corrosion product of CaWO 4 between nitride phosphor (CaAlSiN 3 :Eu 2+ ) and borosilicate glass (BS-glass) was found and investigated in detail firstly to determine the sintering temperature . Laminated structure of PiFS with red layer inside and green layer outside was intentionally designed to effectively avoid “reabsorption” effect between the red and green emitting phosphors. Compared with the opposite laminated structure, the PiFS exhibited the higher luminance efficiency (LE) and better optical properties (Ra = 85, CCT = 5362, CIE = (0.3348, 0.3156)) in wLDs. Notably, the adjustable optical characteristics can be achieved by changing the concentration of phosphor, the number of printing layers and the driving current for the application of PiFS in wLED and wLDs. High quality white light in wLED with CIE coordinates (0.3679, 0.3648) was also acquired and showed the excellent color rendering property (Ra = 90.8) and low color correlated temperature (CCT = 4280 K). Further, the working temperature of PiFS stabilized at 47 °C when applied in wLDs (1 W), which greatly prevented the phenomenon of “thermal quenching” for the phosphors caused by high temperature under high power LDs. Thus, high Ra PiFS prepared by this strategy has better heat dissipation and optical properties than PiG, indicating a prospective application in high-power white LEDs/LDs.
研究领域:
材料科学
·
光电
·
固态照明
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高影响因子
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