Materials
·
2024
·Vol. 17
·期 20
·4954
·
IF 3.1
Wenhui Lou,Yang Tang,Haohong Chen,Yisong Lei,Hui Lin,Ruijin Hong,Zhaoxia Han,Dawei Zhang
Eu 3+ -doped Y 2 O 3 -based luminescent materials can be used as a scintillator for electron or high energy β-ray irradiation, which are essential for applications such as electron microscopy and nuclear batteries. Therefore, it is essential to understand their defect mechanisms and to develop materials with excellent properties. In this paper, Y 2 O 3 -based transparent ceramics with different Eu 3+ doping concentrations were prepared by solid-state reactive vacuum sintering. This series of transparent ceramic samples exhibits strong red emission under electron beam excitation at the keV level. However, color change appears after the high-energy electron irradiation due to the capture of electrons by the traps in the Y 2 O 3 lattice. Optical transmittance, laser-excited luminescence, X-ray photoelectron spectroscopy (XPS), and other analyses indicated that the traps, or the color change, mainly originate from the residual oxygen vacancies, which can be suppressed by high Eu doping. Seen from the cathodoluminescence (CL) spectra, higher doping concentrations of Eu 3+ showed stronger resistance to electron irradiation damage, but also resulted in lower emissions due to concentration quenching. Therefore, 10% doping of Eu was selected in this work to keep the high emission intensity and strong radiation resistance both. This work helps to enhance the understanding of defect formation mechanisms in the Y 2 O 3 matrix and will be of benefit for the modification of scintillation properties for functional materials systems.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
IONICS
·
2023
·Vol. 29
·期 10
·4013-4024
·
IF 2.8
Shang Haixin,Huang Zhiliang
Mono-doped lanthanum silicate solid electrolyte ceramics with phosphorus was successfully prepared by using the urea-nitrate combustion method at 600 °C. The crystal structure and morphology were analyzed by scanning electron microscope (SEM), infrared spectrometer (IR), and X-ray diffractometer (XRD), and the results showed that the successful doping of phosphorus into the lanthanum silicate electrolyte did not destroy the unique crystal structure of the space group P6 3 /m, and the best-sintered morphology of lanthanum silicate was achieved at 1500 °C. Meanwhile, the impedance test was conducted at 600 °C using electrochemical impedance spectroscopy (EIS), and the experimental data showed that with the increase of phosphorus doping, the conductivity of La 9.33 Si 6- x P x O 26+x/2 ( x = 0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8) first increased and then decreased. Also, at x = 0.4, the conductivity of the electrolyte reached a maximum of 7.27 mS/ cm (800 °C), which is because when phosphorus enters the Si site in the lanthanum silicate crystal structure, interstitial oxygen is generated in the 6 3 channel of the structure to maintain the electrovalent balance, and the increase in the concentration of interstitial oxygen increases the conductivity of the electrolyte. Therefore, an enhanced conductivity mechanism with defects in interstitial oxygen concentration is proposed.
研究领域:
材料科学
·
固态离子学
✓ 已验证
DOI
高影响因子
ADVANCED MATERIALS
·
2023
·Vol. 35
·期 24
·2212213
·
IF 29.4
Ziwan Du,Yuxuan Lai,Ruirong Bai,Bolun Wang,Qiang Zheng,Chuan Xu,Teng Lu,Jun Pei,Wei Li,Yu-Ning Wu,Kai Liu,Yun Liu,Engang Fu,Jing-Feng Li,Yigang Yang,Qian Li
Direct neutron detection based on semiconductor crystals holds promise to transform current neutron detector technologies and further boosts their widespread applications. It is, however, long impeded by the dearth of suitable materials in the form of sizeable bulk crystals. Here, high-quality centimeter-sized LiInP 2 Se 6 single crystals are developed using the Bridgman method and their structure and property characteristics are systematically investigated. The prototype detectors fabricated from the crystals demonstrate an energy resolution of 53.7% in response to α -particles generated from an 241 Am source and robust, well-defined response spectra to thermal neutrons that exhibit no polarization or degradation effects under prolonged neutron/ γ -ray irradiation. The primary mechanisms of Se-vacancy and In Li antisite defects in the carrier trapping process are also identified. Such insights are critical for further enhancing the energy resolution of LiInP 2 Se 6 bulk crystals toward the intrinsic level (≈8.6% as indicated by the chemical vapor transport-grown thin crystals). These results pave the way for practically adopting LiInP 2 Se 6 single crystals in new-generation solid-state neutron detectors.
研究领域:
材料科学
·
核技术应用
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2019
·Vol. 103
·期 3
·1789-1797
·
IF 3.094
Junqi Chen,Ying Tang,Changzhi Yin,Mingyang Yu,Huaicheng Xiang,Chunchun Li,Xianran Xing,Liang Fang
An ultra-low dielectric loss ceramics Mg 2 Ge 0.98 O 4 with olivine structure was fabricated by conventional solid-state route. The phase composition, crystal structure, and microwave dielectric properties were investigated. The phase of Mg 2 Ge 0.98 O 4 is formed to the orthorhombic forsterite structure with a space group Pmnb (62). The dense microstructure and excellent microwave dielectric properties of Mg 2 Ge 0.98 O 4 ceramic were obtained at 1360°C for 4 hours, with relative density ~96.4%, ε r ~ 7.3, Q × f = 112 400 GHz, and τ f ~ −64.6 ppm/°C. The conductive mechanism of Mg 2 Ge 0.98 O 4 in the low frequency (<1 MHz) was studied by the dielectric spectroscopy and the result with E dc = 0.93 eV demonstrates that the defect was contributed to the double ionized oxygen vacancies. The intrinsic dielectric properties of Mg 2 Ge 0.98 O 4 in the microwave region were obtained by infrared reflectivity spectra with ε r ~ 7.13, Q × f = 120 400 GHz. And, acceptable τ f (~+2.6 ppm/°C) of 0.92Mg 2 Ge 0.98 O 4 –0.08CaTiO 3 composite ceramic was obtained by adding the CaTiO3.
研究领域:
材料科学
·
物理学
✓ 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）