JOURNAL OF LUMINESCENCE
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2023
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IF 3.6
Zuodong Liu,Yue Cao,Jiashun Wang,Siya Li,Qilong Shen,Yongsheng Yu,Bingchu Mei,Qiangshan Jing,Peng Liu
Near-infrared pumped up-conversion luminescent PrF 3 and YbF 3 co-doped SrF 2 ceramics were fabricated by the hot-pressing sintering technique, and the pellets were transparent with a primrose yellow appearance. The influence of YbF 3 co-doping levels on the optical qualities and microstructures of ceramics was investigated. We identified the mechanisms to realize up-conversion luminescence in the visible range from 3 P 0,1 levels (Pr 3+ ) under near-infrared wavelength pumping sources other than the near ultraviolet to blue region photons. Yb 3+ ions inducing a broad and intense absorption band at the 900–1050 nm region, and the absorption coefficient and cross-section at 980 nm are 7.57 cm −1 and 4.19 × 10 −21 cm 2 in the ceramic co-doped with 15 wt% YbF 3 , respectively. The intense up-conversion luminescence bands at 480, 520, 540, and 600 nm under 980 nm excitation were attributed to 3 P 0 → 3 H 4 , 3 P 1 → 3 H 5 , 3 P 0 → 3 H 5 and 1 D 2 → 3 H 4 transitions of Pr 3+ ions, respectively.
研究领域:
材料科学
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光学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
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2019
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IF 3.45
Honghui Ding,Yuan Hu,Xiaolei Li,Zhihao Zhao,Huiming Ji
Porous Si 3 N 4 ceramics were fabricated by pressureless sintering at 1550 °C for 2 h with YbF 3 -MgF 2 composite sintering aids, systematically investigated for the effect of sintering aids addition on the microstructure and mechanical properties , further explored the formation process and sintering mechanism. The α-β phase transition rate of all samples approached 100% and MgF 2 showed a positive effect on the elongating of β-Si 3 N 4 crystal grains in morphology. The apparent porosity of porous Si 3 N 4 ceramics ranged from 34% to 39%. In addition, when 2.5 wt% YbF 3 was replaced by the same amount of MgF 2 , the flexural strength sharply increased to 298 MPa, an increase of ~49%, while the porosity increased to 37%, an increase of ~15%. With MgF 2 content increasing from 0 to 7.5 wt%, the structure factor reached a minimum of 3.23 when MgF 2 addition was 2.5 wt%, which demonstrated unparalleled superiority in mechanical properties compared with previous studies due to a more preferred form of morphology of connected rod-like β-Si 3 N 4 crystals network. Besides, our research indicated that MgF 2 addition could develop higher aspect ratio of β-Si 3 N 4 grains and had obviously positive effect on the elongating characteristic of β-Si 3 N 4 grains, which was related to the activation energy variation for nucleation on the different facets.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
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2018
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IF 2.606
Te Qi,Zhihao Zhao,Yongqiang Sun,Hangyuan Zhao,Xiaolei Li,Huiming Ji
Porous Si 3 N 4 ceramics with a unique interlocking microstructure have been fabricated by pressureless liquid-phase sintering with YbF 3 and CaF 2 sintering additives at a relatively low temperature (1550 °C). Phase transition and mass diffusion in the low-temperature sintering process are facilitated by YbF 3 and CaF 2 producing plenty of liquid phase owing to their extremely low melting points. As the content of YbF 3 increases from 8.0 wt% to 9.5 wt% and the CaF 2 decreases from 2.0 wt% to 0.5 wt%, the conversion rate of the phase transition from α-Si 3 N 4 to β-Si 3 N 4 increases from 71.1% to 81.2% and the largest average aspect ratio of the β-Si 3 N 4 grains reaches 10.05. At the same time, the porosity declines from 40.4% to 34.9% and the flexural strength increases from 168.5 MPa to 232.1 MPa.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
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2021
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IF 5.316
Xiaoli Luo,Wu Zhao,Qichen Chen,Mingfeng Zhi
As a matrix material, NaYbF 4 has attracted more and more attention due to its large absorption cross section and high energy transfer efficiency. In this study, lanthanide doped NaYbF 4 upconversion (UC) nano-/micro-crystalline was carefully synthesized by hydrothermal method . The influence of kinds of external conditions, including reaction time, initial reaction solution pH value, organic solvents codoping, and Na + concentration on crystalline phase, size, morphology and especially luminescent property are systematically studied and the possible formation mechanism based on PH values is emphatically proposed. The products of NaYbF 4 with various morphologies range from nanospheres , microprisms, microdisks, hexagonal crown-capped shapes, hexagonal clam-like shapes and hexagonal flower-like shapes were successfully prepared. The results show that the up-conversion luminescence property is positively correlated with the slenderness ratio. Solvents codoping and Na + concentration can greatly improve the luminescence property, especially for red emission. Impressively, the emission colors and intensities might be finely tuned through finely tuning the PH values, solvents co-doping and Na + dosage. Furthermore, this study will be expected to contribute to the synthesis of various morphologies and improving the UC intensity of lanthanide doped crystals.
研究领域:
材料科学
·
光学
✓ 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）