JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Guoqiang Luo,Ganrong Zhang,Luo Bai,Ying Zhang,Yuxin Fan,Yuzhe Han,Xiaoping Guo,Meijuan Li,Rong Tu,Qiang Shen
Tetragonal BaTiO 3 (BT) powder with appropriate size and dispersity is essential for the dielectric layers in multilayer ceramic capacitor technology. In this work, high tetragonality BT powder with controllable dispersion, and particle size was synthesized using combined dispersants and a two-step hydrothermal method . Owing to the synergistic effect of chemical bond force and electrostatic adsorption force between cetyltrimethylammonium bromide (CTAB) and polyvinyl-pyrrolidone (PVP) composite dispersants at a high temperature, the ultrafine BT powder with a high c/a of 1.0090, small size of 236 ± 15 nm and low polydispersity index of 0.336 was achieved. This idea shows great significance for the synthesis of BT powder with high tetragonal, high dispersion, and small particle sizes.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 3
·2100-2110
·
IF 2.22
Fan Lele,Liu Zhonghu,Zhu Yiyu,Wang Zhiqiang,Zhao Sihan,Zhu Lei,Zhang Qinfang
In this work, Li x BiO y compounds were synthesized via a facile calcination method. It was surprising that the as-prepared Li 7 BiO 6 compounds transformed into Li-doping tetragonal Bi 2 O 3 phase after undergoing water washing disposal, which was well verified by combining XRD and HR-TEM. In addition, the energy bandgap of prepared compound was derived based on UV–Vis diffuse reflectance spectrum and results indicate the formation of a lower band gap when increasing Li dopant concentration. Moreover, the Li-doping tetragonal Bi 2 O 3 exhibited high visible light-driven photocatalytic activity and the methylene blue can be well degraded in 10 min. The enhanced photocatalytic activity was ascribed to the improvement of light response and charge transfer. Our current work will boost the development of photocatalysis and bring insight into other Li x MO 6 (e.g., Li 6 WO 6 , Li 7 TabO 6 , Li 7 NbO 6 , Li 8 ZrO 6 ) compounds to extend their photocatalytic application.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
Inorganic Chemistry Frontiers
·
2022
·Vol. 10
·期 4
·1215-1224
·
IF 7.779
Jiaqi Ding,Hangren Li,Guoqiang Xi,Jie Tu,Jianjun Tian,Linxing Zhang
The wide band gap of bismuth ferrate-based materials limits their application in optoelectronic devices, and how to achieve band gap modulation in the simplest manner is the primary requirement for their industrialization. BiFeO3 (BFO) films can achieve narrower bandgaps than those under substrate strain, interphase strain, or chemical strain. In this study, we have achieved simultaneously increased tetragonality and reduced bandgaps in the tetragonal-like phase BFO-based films through chemical strain. Co substitution can be controlled by both stoichiometric ratios and atomic deposition rates. The tetragonality can increase up to a large c/a of 1.239, and the bandgap can decrease to 1.45 eV from 2.21 eV. The oxygen vacancies are closely related to the decrease of the band gap. Density functional theory calculations indicate that the introduction of Co and oxygen vacancies essentially reduced the conduction band bottom, resulting from the hybridization energy levels of Co 3d and O 2p, respectively. This paper provides a new strategy for the regulation of the optical band gap of BFO and further reveals its underlying mechanism.
研究领域:
材料科学
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物理学
·
光学工程
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DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2020
·Vol. 126
·期 4
·1-9
·
IF 1.81
Qian Haoyu,Zhu Guisheng,Xu Huarui,Zhang Xiuyun,Zhao Yunyun,Yan Dongliang,Hong Xianyong,Han Yin,Fu Zhenxiao,Ta Shiwo,Yu Aibing
Tetragonal-phase BaTiO 3 powders of particle size 370 nm were synthesized by microwave sintering at 850 °C. The raw materials were BaCO 3 , TiO 2 , and alanine. SiC microspheres were used as microwave conductors. The effects of the holding time, sintering aids, and SiC addition on the preparation of BaTiO 3 were investigated. The results indicate that the addition of SiC as a microwave acceptor leads to formation of microwave micro-regions. This enables uniform heating of the raw materials and decreases the calcination temperature needed to obtain BaTiO 3 . Alanine coordinates with Ba, and this loosens the metal–CO 3 bond and promotes separation of CO 2 , decreases the BaCO 3 decomposition temperature, and provides a higher nucleation site density. It gives an idea about the microwave solid-state synthesis of BaTiO 3 powder.
研究领域:
材料科学
·
无机化学
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产品关联
DOI
高影响因子
RSC Advances
·
2015
·Vol. 5
·期 43
·34451-34455
·
IF 3.84
Yu Liu,Weidong Chi,Hui Liu,Yueyang Su,Liang Zhao
Cubic and tetragonal ZrO2 were synthesized by a sol–gel method using ethanol and glycerol as solvents and ZrOCl2·8H2O as zirconium source. The effect of phase stabilization with amorphous carbon was observed and discussed. The structural evolution, phase transformation and morphological characteristics of powders were investigated by thermogravimetric analysis (TG), differential scanning calorimetric analysis (DSC), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Cubic and tetragonal phase could be generated in this system.
研究领域:
材料科学
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陶瓷学
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产品关联
DOI
高影响因子
RARE METALS
·
2023
·Vol. 42
·期 12
·4189-4200
·
IF 8.8
Xie Yong-Shuai,Peng Ying,Deng Zhe-Zhe,Zhu Ze,Cheng Yuan,Ma De-Hua,Zhu Lu-Yi,Zhang Xing-Hong
ZrO 2 fiber is a promising high-temperature resistant and heat-insulating fiber material. However, the decrease in mechanical properties caused by grain growth at high temperatures seriously affects its application. How to achieve the synergy of its temperature resistance and the thermal insulation performance is still the focus of the current industry. In this work, we started with doping inequivalent elements and studied the phase composition, temperature resistance, and thermal insulation properties of Y 2 O 3 -ZrO 2 ceramic fibers by adjusting the Y/Zr molar ratio. The results showed that Y 2 O 3 could enter the crystal lattice of ZrO 2 and form a solid solution. With the increase in Y 2 O 3 content, the structure of fibers changed from a tetragonal phase to a cubic phase, and the configurational entropy of the system increased. The larger configuration entropy in the sample could produce a robust steric hindrance effect, inhibiting grain growth. After heat treatment at 1300 °C, the grain size of Y 2 Zr 2 O 7 (Y5Z5) fibers was only 61.8% that of Y 0.1 Zr 0.9 O 1.95 (Y1Z9) fibers. The smaller grain size made the Y5Z5 fibers still have excellent flexibility and deformation recovery performance after heat treatment at 1300 °C and could still return to the original state after 85% compression or folded in half. In addition, due to the larger configurational entropy, the mean free path of phonon scattering was shortened, thereby improving the thermal insulation performance of the fiber. In short, this work achieves the synergistic effect of temperature resistance and thermal insulation properties of zirconia-based fiber materials only through simple inequivalent element doping. Graphical abstract
研究领域:
材料科学
·
陶瓷材料
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产品关联
DOI
高影响因子
Nature Communications
·
2021
·Vol. 12
·期 1
·1-9
·
IF 14.919
Gao Xiaoyi,Cheng Zhenxiang,Chen Zibin,Liu Yao,Meng Xiangyu,Zhang Xu,Wang Jianli,Guo Qinghu,Li Bei,Sun Huajun,Gu Qinfen,Hao Hua,Shen Qiang,Wu Jinsong,Liao Xiaozhou,Ringer Simon P.,Liu Hanxing,Zhang Lianmeng,Chen Wen,Li Fei,Zhang Shujun
(K,Na)NbO 3 based ceramics are considered to be one of the most promising lead-free ferroelectrics replacing Pb(Zr,Ti)O 3 . Despite extensive studies over the last two decades, the mechanism for the enhanced piezoelectricity in multi-elements doped (K,Na)NbO 3 ceramics has not been fully understood. Here, we combine temperature-dependent synchrotron x-ray diffraction and property measurements, atomic-scale scanning transmission electron microscopy, and first-principle and phase-field calculations to establish the dopant–structure–property relationship for multi-elements doped (K,Na)NbO 3 ceramics. Our results indicate that the dopants induced tetragonal phase and the accompanying high-density nanoscale heterostructures with low-angle polar vectors are responsible for the high dielectric and piezoelectric properties. This work explains the mechanism of the high piezoelectricity recently achieved in (K,Na)NbO 3 ceramics and provides guidance for the design of high-performance ferroelectric ceramics, which is expected to benefit numerous functional materials.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 6
·2214
·
IF 3.4
Junzhan Zhang,Shangyi Liu,Zhifeng Tian,Ying Zhang,Zongmo Shi
High entropy perovskite oxides (HEPOs) were a class of advanced ceramic materials, which had attracted much scientific attention in recent years. However, the effect of factors affecting the phase stability of high entropy perovskite oxides was still controversial. Herein, 17 kinds of A-site HEPOs were synthesized by solid-state methods, and several criteria for the formation of HEPOs and phase stability were investigated. Single-phase solid solutions were synthesized in 12 kinds of subsystems. The results show that the phase stability of a single-phase solid solution was affected by the size disorder and configurational entropy. The electronegativity difference was the key parameter to predict the evolution of the cubic/tetragonal phase, rather than the tolerance factor. Cubic HEPOs were easily formed when the electronegativity difference was <0.4, while the tetragonal HEPOs were easily formed when the electronegativity difference was ≥0.4. This study can further broaden the family of HEPOs and is expected to design the phase stability of HEPOs through electronegativity difference.
研究领域:
材料科学
·
陶瓷材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials
·
2023
·Vol. 16
·期 20
·6688
·
IF 3.4
Wenhui Lin,Chaoyang Tang,Feiyu Wang,Yiyu Zhu,Zhen Wang,Yifan Li,Qiuqi Wu,Shuguo Lei,Yi Zhang,Jiwei Hou
We present a straightforward and cost-effective method for the fabrication of flexible photodetectors, utilizing tetragonal phase VO2(A) nanorod (NR) networks. The devices exhibit exceptional photosensitivity, reproducibility, and stability in ambient conditions. With a 2.0 V bias voltage, the device demonstrates a photocurrent switching gain of 1982% and 282% under irradiation with light at wavelengths of 532 nm and 980 nm, respectively. The devices show a fast photoelectric response with rise times of 1.8 s and 1.9 s and decay times of 1.2 s and 1.7 s for light at wavelengths of 532 nm and 980 nm, respectively. In addition, the device demonstrates exceptional flexibility across large-angle bending and maintains excellent mechanical stability, even after undergoing numerous extreme bending cycles. We discuss the electron transport process within the nanorod networks, and propose a mechanism for the modulation of the barrier height induced by light. These characteristics reveal that the fabricated devices hold the potential to serve as a high-performance flexible photodetector.Keywords:tetragonal phase VO2(A);low-cost;high-sensitivity photoresponse;flexible photodetector
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
Journal of Materiomics
·
2020
·
IF 5.797
Xuefeng Liu,Quan Zhang,Jianmin Liu,Tao Wang,Yanqiao Xu,Jian Liang,Feng Jiang,Guo Feng,Weihui Jiang
The simultaneous control of crystal phase stability and one-dimensional growth has always been the major challenge for the preparation of tetragonal zirconia whiskers. In this study, we report a facile molten salt processing that utilizes CaF 2 as a stabilizer and adsorbent to meet the phase and morphology requirements. The processes of stabilization, phase transition, ion adsorption and formation of special morphology involved in zirconia growth were investigated by XRD, IR, SEM, DTA-TG and TEM. By controlling the amount of CaF 2 (15 wt%) added in the reaction precursor, tetragonal zirconia whiskers with a desired aspect ratio (>16) can be synthesized, which show single crystalline nature and [001] preferred direction. Ca ions doped at low temperature inhibit the occurrence of phase transition, which allows the tetragonal structure to be retained to room temperature. The inducement and pattern of whisker growth are supposed to be F-adsorption and screw dislocation elongation, respectively. The specific selectivity of surface adsorbed ions to certain zirconia crystal planes reduces or even inhibits the epitaxial growth rate in this direction, offering a viable avenue for the morphology modulation of inorganic nanomaterials.
研究领域:
材料科学
·
晶体学
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产品关联
DOI
高影响因子
Chemosensors
·
2024
·Vol. 12
·期 4
·62
·
IF 3.7
Lu Li,Xuesong Qu,Guo-Hui Pan,Jung Hyun Jeong
In this paper, we report on the solvothermal preparation and detailed characterization of pristine and intentionally doped zirconium dioxide (ZrO2) nanocrystals (NCs, ~5 nm) with Eu3+or Ti4+/Eu3+ions using alkoxide precursors. The results indicated that the ZrO2NCs were dominantly of a tetragonal phase (t-ZrO2) with a small proportion of monoclinic ZrO2(m-ZrO2). The high purity of t-ZrO2NCs could be synthesized with more Eu3+doping. It was found that the as-obtained ZrO2NCs contain some naturally present Ti4+ions originating from precursors, but were being overlooked commonly, and some carbon impurities produced during synthesis. These species showed distinct photoluminescence (PL) properties. At least two types of Eu3+, located at low- and high-symmetry sites (probably sevenfold and eightfold oxygen coordination), respectively, were demonstrated to build into the lattice structure of t-ZrO2NCs together. The cationic dopants were illustrated to be distributed non-randomly over the sites normally occupied by Zr, while Ti impurities preferentially occupied the sites near the low-symmetry site of Eu3+, yielding efficient energy transfer from the titanate groups to the neighboring Eu3+. Luminescence nanothermometry could measure temperature in a non-contact and remote way and could find great potentials in micro/nano-electronics, integrated photonics, and biomedicine. On the basis of the dual-emitting combination strategy involving the white broadband CT (Ti3+→O−) emissions of the titanate groups and red sharp Eu3+emissions, t-ZrO2:Eu3+nanophosphors were demonstrated to be ratiometric self-referencing optical thermometric materials, with a working range of 130–230 K and a maxima of relative sensitivity of ~1.9% K−1at 230 K.
研究领域:
材料科学
·
纳米技术
·
光学
·
测温技术
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2014
·Vol. 98
·期 1
·331-337
·
IF 2.428
Kuo Jiang,Songbai Liu,Wenjun Xi
The 40 mol% CeO 2 -stabilized ZrO 2 ceramic was synthesized by the sol-spray pyrolysis method and aged at 1400°C–1600°C. The effects of high-temperature aging on its fracture toughness were investigated after heat treatments at 1500°C for 6–150 h in air. Characterization results indicated that the activation energy for grain growth of 40 mol% CeO 2 -stabilized ZrO 2 was 593 ± 47 kJ/mol. The average grain size of this ceramic varied from 1.4 to 5.6 μm within the aging condition of 1500°C for 6–150 h. The Ce-lean tetragonal phase has a constant tetragonality (ratio of the c -axis to a -axis of the crystal lattice) of 1.0178 during the aging process. It was found that the fracture toughness of 40 mol% CeO 2 -stabilized ZrO 2 was determined to be 2.0 ± 0.1 MPa·m 1/2 , which did not vary significantly with prolonging aging time. Since no monoclinic zirconia was detected in the regions around the indentation crack-middle and crack-tip, the high fracture toughness maintained after high-temperature aging can be attributed to the remarkable stability of the tetragonal phase in 40 mol% CeO 2 -stabilized ZrO 2 composition.
研究领域:
材料科学
·
陶瓷工程
✓ 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）