Journal of Materials Chemistry C
·
2024
·Vol. 12
·期 46
·18819-18828
·
IF 5.7
Jinyang Li,Wenye Deng,Yan Xue,Ni Ai,Kai Ding,Xianghui Chen,Weiwei Meng,Pengjun Zhao,Aimin Chang,Yongxin Xie
The hexagonal perovskite oxide Ba7Nb4MoO20 is widely studied in chemical devices due to its oxide-ionic conductivity at high temperatures. Ce4+ doping into Ba7Nb4MoO20 was undertaken to optimize small polariton conduction and oxide ionic conductivity simultaneously. Ba7Nb4−xCexMoO20 materials were synthesized via solid phase sintering. XRD patterns indicate a single phase, SEM scans reveal increased densification with higher Ce doping concentrations, and the resistance temperature range expands from 400–900 °C to 300–1100 °C. Hall tests confirm that Ba7Nb4−xCexMoO20 carriers are electrons, indicating n-type conductivity. Nyquist plots illustrate that grain boundary resistance governs complex impedance, which shows gradual oxide ionic conductivity enhancement with rising temperature. The aging drift rate decreases to about 1%, suggesting good stability of Ba7Nb4−xCexMoO20 ceramics. These findings propose a feasible doping strategy for enhancing hexagonal perovskite oxide ceramics.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
National Science Review
·
2024
·
IF 16.3
Huang Yuling,Gong Shaokuan,Chen Qianxia,Chen Congcong,Yang Zhangqiang,Wang Kang,Xue Jie,Wang Daozeng,Lu Haipeng,Mao Lingling,Yang Ye,Zhao Jin-Zhu,Chen Xihan
Halide perovskites have attracted substantial attention recently. However, the strong lattice distortion effects in these materials have led to debates regarding the nature of charge carriers. While the behavior of carriers in bulk three-dimensional materials is well-documented, the characteristics of carriers in two-dimensional perovskites remain less well understood. In this study, we provide direct and clear evidence of small polaron formation through transient spectroscopic analysis of deformation potential and dynamic lattice screening. Coherent acoustic phonon wave signals reveal a strong coupling between carriers and lattice degrees of freedom, leading to small polaron formation and a spin lifetime enhancement of up to 10-fold. Utilizing optical Kerr spectroscopy and theoretical modeling, we observed a notably long polarization response time at room temperature, attributed to lattice distortion and small polarons approximately two-unit cells in size. Temperature-dependent coherent phonon dynamics and X-ray diffraction further confirmed the presence of small polarons. This discovery underscores the significance of the cooperative interplay between exciton dynamics and the small polaron field, particularly in influencing the Coulomb exchange interaction of excitons.
研究领域:
材料科学
·
物理化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yue Xian,Yafei Liu,Ruifeng Wu,Donglin He,Aimin Chang,Bo Zhang
For high temperature thermistor applications, the MgAl 2 O 4 exhibits poor conductivity and requires high sintering temperature for ceramic densification. In this study, we have reported on the preparation and characterization of spinel Mg 0.5 Mn 0.5 AlFeO 4 ceramics by solid solution modification. The resultant ceramics exhibit a combination of high temperature stability and semi-conductivity, which are the characteristics of MgAl 2 O 4 and MnFe 2 O 4 . The material has a moderate thermistor constant, which is in favor of application at high temperatures and a wide temperature range. The electrical conductivity is due to the small-polaron hopping in different valence states of manganese and iron ions . Our findings demonstrate a promising approach to extend the applicability of spinel ceramics for high temperature thermistors.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2013
·Vol. 24
·期 8
·3095-3100
·
IF 1.486
Gao Feng,Zhang Jing,Song Hongzhang,Qin Zhen,Yang Delin,Hu Xing
The influence of Fe doping on the lattice structure and thermoelectric properties of GdBaCo 2− x
Fe
x
O 5+ δ
( x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) ceramics was studied from room temperature to 525 K. The results show that presence of Fe will increase both electrical resistivity and Seebeck coefficients of the samples. Due to the lattice misfit and carrier concentration reduction caused by Fe, the thermal conductivity of the sample decreases. The activation energy of conductivity is larger than that of thermopower calculated in the semiconductive region, which means that the conduction mechanism may be determined as a small polaron hopping model. The optimum Fe doping amount is x = 0.6, which results in a ZT value 0.02 at 373 K.
研究领域:
材料科学
·
凝聚态物理
·
功能陶瓷
·
热电材料
·
固态离子学
✓ 已验证
DOI
高影响因子
Journal of Physical Chemistry C
·
2022
·
IF 4.177
Zhaoshi Yu,Leqi Chen,Li Luo,Rui Huang,Zhixin Tang,Peng Xiao,Yunhuai Zhang
Ti doping can improve the photoelectrochemical water splitting performance of hematite. However, the effect of doping on regulating small polaron hopping in the bulk and charge transfer properties on the solid–liquid interface is not fully understood. In this paper, we investigate the effects of titanium doping on hematite by decoupling a hematite homojunction structure into bulk and surface layers. We found that 3% Ti doping remarkably reduces the small polaron hopping (SPH) barrier, which leads to the high bulk charge transport, and 5% Ti doping significantly passivates the recombination of the surface states (r-SS) of hematite and promotes the conversion of the surface holes to long-lived reaction intermediates (i-SS) on the solid–liquid interface, which leads to the high surface charge transfer. Based on the above results, we report first an unconventional Ti-doped hematite homojunction design that is established with 3% Ti-doped hematite as the underlayer and 5% Ti-doped hematite as the surface layer. The homojunction exhibits a significantly enhanced photocurrent density (1.27 mA cm–2) compared to that of the typical type-II hematite structure at 1.5 VRHE. This work has well demonstrated a new homojunction design strategy for enhancing the photoelectrochemical water splitting.
研究领域:
材料科学
·
电化学
·
可再生能源
·
光电化学
✓ 已验证
DOI
高影响因子
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