CHEMISTRY OF MATERIALS
·
2019
·
IF 10.159
Ziyan Wu,Qiqi Zhang,Binghan Li,Zhifang Shi,Kaimin Xu,Yi Chen,Zhijun Ning,Qixi Mi
All-inorganic metal halide perovskites are noted for their excellent optoelectronic properties and good chemical stability but also a propensity to transform into nonperovskite phases. A case in point is lead-free CsSnCl3, whose perovskite Phase I is metastable at room temperature and could not be stabilized by partial substitution of Cs+ or Cl–. Judging from the radii of the constituent ions of CsSnCl3, we paid attention to octahedral cations smaller than Sn2+ and selected Mn2+ and In3+ for substitution at the B-site. A quantitative structural indicator, volume per formula unit (V/Z), guided the syntheses of CsSn0.9Mn0.1Cl3 (CTMC) and CsSn0.9In0.067Cl3 (CTIC), which are shown by single-crystal X-ray diffraction and differential scanning calorimetry to be homogeneous, stable perovskite phases at room temperature. CTMC turns into a disordered perovskite structure at 193 K, lower than the corresponding transition temperature of CsSnCl3 by nearly 100 K. Vacancies in CTIC result in a more flexible crystal structure than CTMC and CsSnCl3. CTMC and CTIC appear bright yellow with a steep absorption edge at ∼450 nm, and their photoluminescence peaks are located at 645 and 484 nm, respectively, with intensities significantly enhanced from CsSnCl3. Energy transfer processes are proposed to account for the Stokes shifts in the photoluminescence of CTMC and CTIC. Thin films of CTMC glow red under ultraviolet excitation and hold promise for electroluminescence devices. This study gives insights into the structural and electronic effects of ionic substitution in CsSnCl3 and can be extended to other metastable perovskite phases.
研究领域:
材料科学
·
光电
·
固体化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2020
·Vol. 47
·期 5
·6842-6847
·
IF 3.83
Shunjin Xiong,Rongxia Huang,Congfei Peng,Yejing Dai,Jiajiu Li,Wen Bai,Hua-Tay Lin
A series of HfO 2 -modified (Bi 0 .475 Na 0 . 405 K 0 . 055 Li 0.015 ) 0.95 Ba 0 . 05 Ti (1- x ) Hf x O 3 ( x = 0–0.015) lead-free ceramics were prepared. Results of detailed characterizations showed that the addition of HfO 2 had little influence on the grain size, and all of the samples showed the pure perovskite structure. As the Hf 4+ content increases, the samples changed from the normal ferroelectric phase to the ergodic relaxor state at room temperature, and the ceramics with x = 0.01 showed a high electro-strain of 0.295% at 6 kV/mm. Therefore, this study provides a new insight into of how the HfO 2 addition influences the ferroelectric property of the BNT-based ceramics by B-site substitution.
研究领域:
材料科学
·
无机非金属材料
·
功能陶瓷
·
铁电材料
·
压电材料
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2025
·
IF 6.2
Yuan-Bin Chen,Ling Tang,Xiuyuan Su
Low-temperature sintered microwave dielectric ceramics are gaining increasing attention for next-generation wireless communication systems, particularly within the 6 G frequency range. However, materials that simultaneously exhibit ultra-low dielectric loss and low sintering temperatures remain scarce. In this study, Nd 2 [Zr 1-X (Bi 0.5 Ta 0.5 ) X ] 3 (MoO 4 ) 9 ceramics were prepared via a conventional solid-state reaction method and exhibited a single-phase structure with a trigonal symmetry (space group R 3 ¯ C, No. 167). The optimal sample at x = 0.11 sintered at 750 ℃ showed excellent performance: ε r = 11.4, Q×f = 186,300 ± 8900 GHz, and τ f = –42.9 ppm/℃. The elevated Q×f value is chiefly ascribed to increased lattice energy, with its variation more plausibly arising from intrinsic effects within the material. The dielectric constant (εᵣ), analyzed using the Clausius–Mosotti equation, was predominantly influenced by ionic polarizability. According to P–V–L theory, the effective bond strength f iNd–O played a major role in determining εᵣ, while τ f was governed by the bond energy and thermal expansion behavior of Mo–O bonds. Raman spectroscopy further confirmed the structure–property relationships. These results suggest that B-site substitution with (Bi 0.5 Ta 0.5 ) 4+ not only promotes densification and increases lattice energy, but also maintains thermal stability, thereby enhancing Q×f without compromising τ f . This system offers strong potential for integration into future microwave dielectric components.
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2017
·Vol. 42
·期 34
·22294-22301
·
IF 3.582
Jiang Li,Tianmu Lv,Nianjun Hou,Ping Li,Xueli Yao,Lijun Fan,Tian Gan,Yicheng Zhao,Yongdan Li
The effects of Mo doping into the B-site of La 0.3 Sr 0.7 TiO 3-δ perovskite on its ionic conductivity and catalytic activity as an anode material of solid oxide fuel cells have been investigated. The partial substitution of Ti by Mo reduces the bond energy between metal and oxygen ions in the perovskite. The concentration of Mo 5+ /Mo 6+ redox couples increases with the rise of the content of Mo, while the oxygen ionic conductivity decreases simultaneously. The doping of Mo significantly reduces the anodic polarization resistance and improves the performance of the single cell. The cell with La 0.3 Sr 0.7 Ti 0.97 Mo 0.03 O 3-δ anode and La 0.8 Sr 0.2 Ga 0.8 Mg 0.2 O 3-δ electrolyte exhibits a maximum power density of 135 mW cm −2 at 850 °C with hydrogen as fuel.
研究领域:
材料科学
·
电化学
·
能源材料
·
固态离子学
·
燃料电池技术
✓ 已验证
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 23
·
IF 3.2
Wenjie Zhou,Tao Du,Changbai Long
High-efficiency, lead-free dielectrics are sought for pulsed-power capacitors, yet pristine Bi0.5Na0.5TiO3(BNT) suffers from large remanence, high coercivity, and limited breakdown strength. Here, we report (1 − x)Bi0.5Na0.5Ti0.97Nb0.03O3-xSr0.85Ba0.15Ta0.5+0.02xAl0.5−0.02xO3(BNTNb–SBTA, x = 0–0.15) ceramics synthesized via solid-state reaction, achieving enhanced relaxor ferroelectric behavior through multi-cation substitution at A- and B-sites. X-ray diffraction confirms a pure perovskite solid solution, while scanning electron microscopy reveals grain refinement, suppressing oxygen vacancies and boosting the breakdown strength. Raman and dielectric analyses evidence strengthened relaxor behavior, accompanied by loop slimming and a systematic rise in breakdown strength. The composition x = 0.10 achieves the best trade-off, deliveringWrec= 3.357 J cm−3andη= 90.5% atEb= 240 kV cm−1. Robust operational stability is demonstrated with small variations ofWrec/ηover 0.1–200 Hz, 25–175 °C, and 106cycles. Pulsed tests show fast discharge (∼26 ns) withWd= 0.826 J cm−3at ∼90% efficiency under moderate fields. These results indicate that synergistic A/B-site disorder (Sr/Ba on A-site; Ta/Al with Nb on B-site), combined with microstructural densification, effectively minimizesPrwhile elevatingEb, enabling high-efficiency energy storage under practical operating conditions.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）