CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Yajie Wang,Ziyi Zhang,Jie Li,Ying Tang,Liang Fang
Excellent spinel microwave dielectric ceramics (1- x )Zn 2 TiO 4 - x Li 2 MgTi 3 O 8 (ZTLMT x , x = 1/3 and 2/3) were prepared at relatively low densification temperatures of 1100 °C and 1080 °C, respectively. A disordered cubic phase with space group Fd -3 m was formed at x = 1/3, whereas an ordered cubic phase with space group P 4 3 32 was formed at x = 2/3. The ceramics at x = 1/3 and 2/3 exhibited promising microwave dielectric properties of ɛ r = 18.27 and 22.96, Q × f = 91,877 GHz and 75,186 GHz, and τ f = −42.3 ppm/°C and −21.05 ppm/°C, respectively. The large deviation between the experimental ԑ r and theoretical ε th of 1/3 and 2/3 ceramics were 18.3 % and 57 %, respectively, due to the underestimation of the ionic polarizability of Ti 4+ . The difference in their ɛ r , Q × f , and τ f were discussed by the structure, FWHM of A 1g , lattice energy and bond energy in detail.
研究领域:
材料科学
·
陶瓷学
·
物理学
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Ziyang Wu,Changheng Chen,Jinmeng Xiang,Jiwen Chang,Xiaoqi Zhao,Chongfeng Guo
The portable near-infrared (NIR) phosphor-converted light-emitting diodes (pc-LEDs) with a broad spectrum have great application potential in information encryption, infrared night vision, medical imaging, chemical component detection, nondestructive testing, and many other fields, in which stable and efficient ultrawide NIR-emitting phosphors have become a new pursuit. However, the low luminescence intensity and narrowband emission of most NIR phosphors limit their potential applications. Under this drive, a NIR-emitting phosphor, Li2MgTi2.99O8:0.01Cr3+ (LMT:0.01Cr3+), with TiO6 and MgO6 octahedral sites for Cr3+, was developed. It exhibits 79.28% internal quantum efficiency (IQE) and a 155 nm full width at half maximum (fwhm) in the range of 600∼1300 nm. Based on the weakened crystal field strength through the [In3+-In3+] unit to cosubstitute the [Ti4+-Mg2+] unit, the emission peak red-shifted from 751 to 772 nm, with the fwhm widening to 205 nm in Li2Mg0.98In0.04Ti2.97O8:0.01Cr3+phosphors (LMIT:0.01Cr3+). The IQE was also further enhanced to 85.02% by substituting Mg2+ in LMIT:0.01Cr3+ with Zn2+, increasing the index of lattice distortion at the luminescence center to get Li2Mg0.92In0.04Zn0.06Ti2.97O8:0.01Cr3+ (LMIZT:0.01Cr3+). NIR pc-LED devices were fabricated by combining LMIZT:0.01Cr3+ phosphor with a blue LED chip, and their potential applications were also evaluated, showing excellent prospects in NIR penetration imaging and information encryption.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INORGANIC CHEMISTRY
·
2026
·
IF 4.6
Yingfang Li,Long Tian,Hai Wu,Xiaohuan Long,Xu Wang,Chaoyong Deng,Weichao Huang
Fe3+-activated luminescent materials have recently evoked considerable interest owing to their environmentally friendly and versatile applications potential. In this study, novel Li2MgTi3O8: Fe3+ phosphors are synthesized and its luminescence properties were systematically investigated. The Li2MgTi3O8: Fe3+ phosphor exhibits a broad excitation spectrum covering the ultraviolet–visible region from 250 to 600 nm. Upon 417 nm excitation, the as-prepared phosphor shows a broad far-red emission band centered at 709 nm due to the 4T1 (4G) → 6A1 (6S) transition of Fe3+ ions, along with a good internal quantum efficiency (IQE) of 39%. Importantly, the emission band of phosphors can be well matched with the absorption spectra of plant pigments. Furthermore, the temperature sensing properties of the phosphor samples were analyzed by using the fluorescence intensity (FI) and fluorescence lifetime (FL) technique, achieving maximum relative sensitivities (Sr) of 1.73% K–1@423 K and 3.52% K–1@373 K, respectively. These results indicate that Li2MgTi3O8: Fe3+ phosphors have potential applications for optical thermometry and plant growth illumination.
✓ 已验证
DOI
PubMed
高影响因子
IONICS
·
2020
·Vol. 26
·期 10
·4937-4948
·
IF 2.394
Tian Leiwu,Yuan Haifeng,Shao Qinjun,Zaidi Syed Danish Ali,Wang Chong,Chen Jian
Surface modification plays a vital role in improving the rate performance and cycling stability of layered Ni-rich LiNi 0.6 Co 0.2 Mn 0.2 O 2 (NCM622) cathode materials for Li-ion batteries. In this study, Li 2 MgTi 3 O 8 (LMTO)-coated NCM622 was successfully synthesized by wet coating combined with sintering process. The results of morphological analysis showed a uniform LMTO layer coated on the surface of NCM622 materials. The dual ions of Ti 4+ and Mg 2+ on surface structure of NCM622 were identified by X-ray diffraction and X-ray photoelectron spectroscopy. The surface coating layer prevented the direct contact between the active cathode material and the electrolyte which significantly reduced the side reactions, and the doping of Ti 4+ and Mg 2+ improved the structural stability of the NCM622 materials. The electrochemical performance indicates that NCM622 cathode with a coating layer of 0.5 wt% LMTO exhibited excellent cycle stability and maintained a capacity retention up to 76% after 200 cycles at 25 °C at 1 C-rate, which was higher than the value of 52% for the NCM622.
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）