Optical Materials Express
·
2022
·Vol. 12
·期 8
·2942-2953
·
IF 3.074
Kai Sun,Xiaomeng Yin,Zhenqing Li,Hui Lin,Ruijin Hong,Dawei Zhang,Zhijun Zhang,Guanhaojie Zheng,Guanhaojie Zheng,Yuchong Ding
MgAl2O4:Cr3+ far-red emitting ceramic phosphors were prepared by the solid-state reaction method. The photoluminescence characteristics, especially the luminescence thermal stability, thermal conductivity, and its application in phosphor-converted LEDs were studied. Under 450 nm excitation, the ceramic phosphors exhibited an emission range of 650-750 nm and showed a narrow-band emission peaked at 688 nm. It also shows 708 nm and 718 nm far-red emission, which matches well with the absorption peak of the plant phytochrome PFR. The luminescence thermal stability of MgAl1.99O4:0.01Cr3+ was excellent. The integral intensity of the two emissions peaked at 708 nm and 718 nm at 500 K can maintain 98.27% and 98.24% of the counterparts measured at room temperature, respectively, showing zero thermal quenching behavior up to 500 K. The thermal conductivity of the MgAl1.99O4:0.01Cr3+ ceramic was 10.3 W·m-1·K-1. These results indicate that MgAl2O4:Cr3+ ceramic phosphors can be applied in plant lighting when packaged onto 450 nm blue LED chips.
研究领域:
材料科学
·
光学工程
·
植物学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Junwei Zhang,Hui Lin,Shuo Zhu,Yuetong Zhen,Ruijin Hong,Zhaoxia Han,Dawei Zhang
The rapid advancement of high-power solid-state lighting highlights the importance of developing phosphor ceramics with high resistance to thermal quenching of its luminescence. Herein, a series of Eu 2+ co-doping MgAl 2 O 4 : Mn 2+ phosphor ceramics were synthesized by spark plasma sintering. The significant green light enhancement at 516 nm is attributed to Eu 2+ -Mn 2+ energy transfer. The introduction of Eu 2+ increases the concentration of electron trap levels and improve the luminescence intensity at 423 K from 80% to 110%, compared with the counterparts at room temperature. The strong correlation between trap levels and oxygen vacancies was demonstrated by the X-ray photoelectron spectroscopy and electron paramagnetic resonance analysis. Finally, the application demonstration of the optimized sample was explored through its integration with a 400 nm LED chip. This study proposes a strategy of leveraging trap levels to induce anti-thermal quenching behavior, providing some insights for the development of highly thermally stable phosphor ceramics.
研究领域:
材料科学
·
发光材料
·
固态照明
·
陶瓷学
·
光电子学
✓ 已验证
产品关联
DOI
高影响因子
OPTICAL MATERIALS
·
2023
·
IF 3.9
Yibo Zhang,Shen Wang,Biao Liu,Yan Hao
MgAl 2 O 4 :Cr 3+ transparent ceramics were prepared by a hot-pressed sintering process with Y 2 O 3 and La 2 O 3 as sintering aids, and the effects on the microstructure, densification, optical transmission, and photoluminescent properties were investigated. The sintering aids of Y 2 O 3 and La 2 O 3 enhanced the relative density, reaching 99.33% with 2.4 wt% Y 2 O 3 and 99.24% with 0.8 wt% La 2 O 3 . La 2 O 3 also inhibited abnormal grain growth and obtained ceramics with uniform grain size. In addition, the optical transmission was also improved with Y 2 O 3 and La 2 O 3 as sintering aids. The transmission of the ceramic with 2.4 wt% Y 2 O 3 exceeded 78% in the region of 700–6000 nm and reached 83% at 1450 nm. Moreover, Y 2 O 3 and La 2 O 3 both contributed to improving the quantum yield of the ceramics, especially for Y 2 O 3 , and the quantum yield was about 0.354, which was approximately two times higher than that without R 2 O 3 . In summary, La 2 O 3 was helpful for improving sintering process, inhibiting grain growth, and homogenizing the grain size, while Y 2 O 3 was significant for enhancing the optical and photoluminescent properties.
研究领域:
材料科学
·
无机非金属材料
·
功能陶瓷
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光电子学
·
固态发光材料
✓ 已验证
DOI
高影响因子
Transactions of the Indian Ceramic Society
·
2020
·
IF 0.952
Shifa Wang,Huajing Gao,Hong Yu,Peiying Li,Yanwu Li,Chaoli Chen,Yong Wang,Liang Yang,Zijuan Yin
MgAl2O4:M (M = Ti, Mn, Co, Ni) phosphors were successfully prepared by a modified polyacrylamide gel method. Calcination temperature and metal particle has significant effects on the phase transition, optical and color properties of Mg Al2O4: M phosphors. Ti, M n, Co and Ni metal particles introduced into the MgAl2O4 system can produce a variety of colours from white, grayish black, blue to turquoise blue. Mn, Co and Ni metal particles added into MgAl2O4 system can extend their light absorption to visible light range, while the Ti metal particles clad into the system did not improve significantly. Co metal particles appended into the MgAl2O4 system can cause fluorescence quenching of emission peak at 395 nm and enhancement of emission peak at 405 nm, while the Ti and Mn metal particles infused into the system can bring the enhancement of visible emission peak at 425 nm. The fluorescence quenching of the peak at 395 nm can be ascribed to the wavelength of Co metal particles matching the surface plasmon absorbance band of MgAl2O4:M phosphor. A reduction in emission intensity at 425 nm can be assigned to electron transfer from the conduction band (CB) of MgAl2O4 to the CB of metal particles causing non-radiative decay.
研究领域:
材料科学
·
光学
·
化学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2023
·Vol. 106
·期 11
·7069-7077
·
IF 3.9
Xiaomeng Yin,Ming Qiang,Hui Lin,Dawei Zhang,Ruijin Hong,Zhaoxia Han
In this work, we fabricated a novel spinel-type phosphor material MgAl 2− x Ga x O 4 doped with Cr 3+ by the high-temperature solid-state sintering method. The crystal field environment of the spinel was tuned by replacing the Al ions with Ga 3+ ions of different concentrations. The cell volume and D q / B gradient increase from 2.82 to 2.62 with increasing Ga 3+ ion doping concentration. This also implies a gradual decrease in the field strength of the crystal. Based on this, the excitation spectra of MgAl 1.995− x Ga x O 4 :0.5%Cr 3+ phosphors yield a redshift. Increasing the Ga 3+ ion doping concentration also improves the emission intensity and thermal stability of the phosphors, and the emission intensity of the Ga 3+ -doped phosphors is significantly increased. For a Ga/Al ratio of 1, the thermal stability of the phosphor emission is optimal. The emission intensity at 140°C can maintain 76% of the emission intensity at room temperature, indicating that appropriate Ga 3+ ion doping can improve the emission efficiency and thermal stability of the phosphors.
研究领域:
材料科学
·
光学
·
荧光粉技术
✓ 已验证
产品关联
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Mi Li,Xiaoyang Deng,Zhenxia Wang,Kai Liu,Zizai Ma,Jianxing Wang,Xiaoguang Wang
Lithium-rich layered oxides (LLO) with ultra-high specific capacity are one of the most promising cathodes for the next-generation lithium-ion batteries. However, the irreversible release of lattice oxygen will cause LLO surface reconstruction and electrolyte decomposition, resulting in low initial coulombic efficiency (ICE), high interface resistance as well as severe voltage and capacity degradation. Herein, a facile and effective strategy is proposed to stabilize the cathode materials by coating the LLO with spinel MgAl 2 O 4 . It is found that the robust MgAl 2 O 4 (MAO) decoration layer can not only alleviate the lattice mismatch to sustain the structure integrity, but also inhibit the side reactions with electrolyte during long-term cycles. Furthermore, density functional theory calculations show that the surface oxygen release energy barrier is increased with the surface decoration of MAO. Accordingly, the coated LLO-based hetero-structured cathode exhibits a higher ICE (80.14%) and lower interface resistance than that of LLO electrode. Moreover, a reversible capacity of 176.6 mAh g −1 (with a capacity retention as high as 78.1%) and small voltage drop of 0.27 V are achieved even after 200 cycles at 1 C. This work sheds new light on the facile preparation and modification of lithium-rich layered oxides-related cathode for high-energy density lithium-ion batteries.
研究领域:
材料科学
·
电化学
·
能源存储
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2016
·
IF 3.014
Jianhua Liu,Xiaojun Lv,Jie Li,Yexiang Liu
MgAl 2 O 4 MgAlON materials as potential candidate sidewalls were prepared by using AlN , MgO , Al 2 O 3 , and nanosized MgAl 2 O 4 powder as starting materials. The reaction sintering of the MgAl 2 O 4 MgAlON materials was investigated by means of X-ray diffraction and scanning electron microscope. All the specimens were corroded in a Na 3 AlF 6 AlF 3 CaF 2 Al 2 O 3 bath to assess the electrolyte corrosion resistance . The results show that reaction sintering occurs in the MgAl 2 O 4 MgO Al 2 O 3 AlN system at 1830 °C and 5 MPa in flowing nitrogen for 5 h. The MgAl 2 O 4 MgAlON specimens are obtained and have high bulk density. The flexural strength increases from 202 ± 6 MPa to 248 ± 8 MPa and the Vickers hardness increases from 9.5 ± 0.2 GPa to 12.6 ± 0.4 GPa with increasing MgAlON content from 10 wt% to 40 wt%. The MgAl 2 O 4 MgAlON materials exhibit a good corrosion resistance to the Na 3 AlF 6 AlF 3 CaF 2 Al 2 O 3 bath owing to their high-density and the formation of the composite spinel in the specimens. The corrosion mechanisms of MgAl 2 O 4 MgAlON composites in molten electrolyte are mainly proposed by the dissolution of MgAl 2 O 4 and the diffusion of fluoride. Corrosion kinetic obeys a nearly parabolic law and the corrosion rate decreases with increasing MgAlON content.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2026
·
IF 4.8
Wenli Wu,Gang Xie,Xinyu Zhang,Daiqi Ye,Limin Chen
A series of Co/MgAl 2 O 4 (CM1A2) catalysts with controlled cobalt loadings (0.5–3 wt%) were successfully synthesized using a co-precipitation method and tested for CO 2 -mediated oxidative dehydrogenation of ethane (CO 2 -ODHE) reaction. 1.5CM1A2 catalyst (1.5 wt%) displays the best catalytic performance, superior to other transition metal-based catalysts with ethane conversion, CO 2 conversion and ethylene yield at 700 °C about 42%, 8% and 38%, respectively. The catalysts were systematically characterized by X-ray diffraction (XRD), Raman spectroscopy, Ultraviolet-visible spectrophotometry (UV–vis), X-ray photoelectron spectroscopy (XPS), and in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). The results reveal that the non-reducible MgAl 2 O 4 support possesses remarkable thermal stability and the obtained catalysts exhibit resistance to dry reforming of ethane (DRE) reaction, facilitating prolonged high catalytic activity and selectivity at 650–700 °C. Co 3+ was primarily in Co 3 O 4 , whereas Co 2+ was identified within both Co 3 O 4 and highly stable CoAl 2 O 4 ; however, Co 2+ /Co 3+ decreases continuously along with cobalt loading increase. In addition, CoAl 2 O 4 promotes ethylene formation. In Co 3 O 4 , Co 3+ is more susceptible to reduction to metallic Co 0 under the reaction atmosphere, promoting reverse water-gas shift (RWGS) reaction and finally enhancing oxidative dehydrogenation of ethane. These insights offer a valuable framework for the rational design of efficient and durable catalysts for the CO 2 -ODHE process.
✓ 已验证
DOI
高影响因子
DALTON TRANSACTIONS
·
2020
·Vol. 49
·期 17
·5711-5721
·
IF 4.174
Haipeng Ji,Xinghui Hou,Maxim S. Molokeev,Jumpei Ueda,Setsuhisa Tanabe,Mikhail G. Brik,Zongtao Zhang,Yu Wang,Deliang Chen
Blue light pumped red luminescence with broadband and high photon-energy emission is highly desired for phosphor-converted white light-emitting diodes (pc-wLEDs), to achieve a high color rendering index and high luminous efficacy. Mn4+-doped red-emitting phosphors generally exhibit sharp vibronic emissions associated with the parity- and spin-forbidden 2Eg → 4A2g transitions. In this paper, two abnormal luminescence behaviors were observed for Mn4+ in the MgAl2O4:Mn4+ spinel phosphor with a short wavelength emission band peaking at 651 nm. Firstly, the Mn4+ 2Eg → 4A2g transition exhibits ultrabroadband luminescence in MgAl2O4 and the large full-width at half-maximum (FWHM) is dependent both on the calcination temperature and on the partial substitution of Al3+ with Ga3+. Secondly, the thermal quenching behavior of the Mn4+ 2Eg → 4A2g luminescence in MgAl2O4 shows a dependence on its thermal treatment and preparation method. The Rietveld refinement and Raman results demonstrate that the variation in the FWHM of the luminescence spectra is a sum effect of structural ordering (i.e., isotropic displacement decrease of constituent atoms) and the Mg ↔ Al anti-site disorder. A model for the observed varying thermal quenching of luminescence was tentatively proposed. The intrinsic thermal quenching temperature of Mn4+ luminescence in MgAl2O4 was found to be 390–400 K using the samples prepared by the co-precipitation and molten salt methods. The present work gives a novel perspective to understand the luminescence spectra of Mn4+ 2Eg → 4A2g transition.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
JOURNAL OF POROUS MATERIALS
·
2025
·
IF 3.2
Zhang Wenlong,Wang Bin,Xu Yuxin,Chen Xiao,Zhang Kuibao,Hao Yan
To enhance the thermal stability of SiO 2 aerogels at high temperature, this study proposes a method involving the incorporation of MgAl 2 O 4 nanoparticles into SiO 2 aerogels to improve their high-temperature stability. By comparing the performance of MgAl 2 O 4 -SiO 2 aerogel with pure SiO 2 aerogels after heat treatment at high temperatures, it is demonstrated that the MgAl 2 O 4 nanoparticles significantly enhances the thermal stability of SiO 2 aerogels at elevated temperatures while almost no effect on thermal conductivity, about 0.0312 and 0.0322 W/(m·K). The MgAl 2 O 4 -SiO 2 aerogels exhibit superior thermal stability and insulation performance compared to pure SiO 2 aerogels at temperatures exceeding 800 ℃. Notably, even after heat treatment at 1100℃, a condition that causes pure SiO 2 aerogels to nearly lose their porous structure, the MgAl 2 O 4 -SiO 2 aerogels retain a specific surface area of 81.95 m 2 /g and thermal conductivity of 0.0584 W/(m·K).
研究领域:
材料科学
·
无机化学
·
热力学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2023
·
IF 22.1
Haokun Bai,Lanlan Liang,Peike Cao,Haiguang Zhang,Shuo Chen,Hongtao Yu,Xie Quan
Heterogeneous catalytic ozonation (HCO) is a promising technology for organic pollutants removal in wastewater treatment owing to the generation of powerful but short-lived hydroxyl radicals (HO·). Herein, we incorporate MgAl 2 O 4 catalysts on the surface of ceramic membrane pores (MgAl membrane) to enhance HO· utilization and promote pollutant degradation under spatial confinement. The MgAl catalytic membrane achieved a removal efficiency of 74.0% for ibuprofen (5 mg/L) with 68.8% total organic carbon (TOC) removal, and the pollutant removal efficiency maintained over 67% in 25 h. Electron paramagnetic resonance (EPR) and scavenging experiments revealed that HO· played the dominant role in pollutant degradation. The catalyst surface hydroxyl groups were identified as active sites to effectively generate HO· via ozone decomposition. This work provides a viable strategy to achieve efficient pollutant degradation in wastewater treatment under spatial confinement in a membrane configuration.
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jian Li,Jia Liu,Yeqing He,Xiaohan Zhang,Yanxiang Jiang,Yang Wang,Wei Sun,Yuanyuan Zhou,Walther Glaubitt,Futian Liu,Haitao Wu,Fei Wang,Ling Li
High-performance dielectric ceramics are vital for next-generation microwave devices, requiring advanced doping and composite strategies to enhance material properties. The (1- x )MgAl 2 O 4 - x Y 3 Al 5 O 12 composite ceramics were found in the MgO-Al 2 O 3 -Y 2 O 3 pseudoternary phase diagram and synthesized via solid-phase reaction. The two phases coexist to improve grain size distribution and achieve a low eutectic temperature, allowing x = 0.1–0.7 samples to gain a dense microstructure ( ρ > 96 %) when sintered at 1650–1670 °C. The semi-coherent interface, coupled with the Mg 2+ /Y 3+ cation transition zone, promotes the formation of a partial solid solution, thereby alleviating interfacial stress at the grain boundaries between MgAl 2 O 4 and Y 3 Al 5 O 12 . Notably, the 0.3MgAl 2 O 4 -0.7Y 3 Al 5 O 12 ceramic exhibits satisfying microwave dielectric properties: ε r = 10.1 ± 0.24, Q × f = 195,000 ± 12,000 GHz, and τ f = −11.9 ppm/°C. In addition to phase composition and microstructure, the enhanced performance can be attributed to the optimized crystal structure. The partial substitution of Y 3+ by Mg 2+ with a smaller radius induced the “rattling” effect and abnormal large permittivity in the [YO 8 ] site. The 27 Al NMR spectra revealed an increase in the Mg-Al inversion degree in the Mg-deficient spinel structure, resulting in the elevated total covalency of the Al-O bond. The structural changes corresponded to a decrease in intrinsic dielectric loss in Mg-Al spinel and an increase in τ f in the Y-Al garnet phase. These findings indicate the (1- x )MgAl 2 O 4 - x Y 3 Al 5 O 12 ceramics have promising applications in the field of HTCC millimeter wave communications.
研究领域:
材料科学
·
电子工程
✓ 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）