Journal of Physical Chemistry C
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2024
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IF 3.3
Jindong Bai,Yongsong Wang,Dingbang Yang,Xiao Guo,Yuedong Wang,Tao Xu,Haipeng Xie,Jin Li,Fangping Ouyang,Han Huang
Twisting between layered materials in close proximity causes reconstruction of the electron and crystal structures. The resulting reconstruction has received increasing attention due to the realization of magic-angle superconductivity, moiré excitons, and moiré ferroelectricity. However, demonstrations of such concepts for phonon polarization have been very limited. Here, we reported on the systematic angle-dependent polarized Raman (ADPR) investigations on the twisted bilayer (tBL) α-MoO3 with each layer in a thickness of ∼14 nm. Under 532 and 633 nm excitation, (i) the Raman intensity (I) of representative Mo–Oc symmetric stretching vibration phonon mode (SVPM) at 818 cm–1 and rigid MoO4 translational vibration phonon mode (TVPM) at 156 cm–1 decreases monotonically with the twist angle (φ) increase and (ii) the polar plots of both modes were tuned from axial symmetry to central symmetry by φ increase. The dependence of I and symmetry of both modes on φ were described semiquantitatively by applying the classical Placzek approximation and the interference effect. Our findings unravel the complex interaction between the twisted layer configurations and phonon behaviors of α-MoO3, providing valuable insights into the anomalous phonon polarization responses in low symmetric two-dimensional materials and potentially facilitating the development of technologies based on tunable phonon polarization.
研究领域:
材料科学
·
凝聚态物理
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Kai Zhang,Yinjie Sun,Yiling Cheng,Sifan Hou,Jinpeng Fan
Inspired by the Bouligand structure in nature, a kind of Inverse-Bouligand structure was designed. Different from the bionic Bouligand structure of a one-dimensional material unit, the inverse-Bouligand structure is obtained by stacking and twisting the ceramic layer with a parallel groove structure. The grooves arranged in parallel are first etched on the ceramic green body and then sintered after stacking and twisting. After sintering, the groove structure can still be maintained, so the resulting laminated twisted groove structure in the bulk forms an inverse-Bouligand structure, which can promote crack deflection and improve the toughness of the material during the fracture process. After testing different twist angles, the results show that when the twist angle is 15°, the toughness of the material can reach 11.22 ± 1.77 MPa m 1/2 , and high strength can be guaranteed. The synergistic effect of interlayer crack deflection and regional crack twist is the main mechanism for the improvement of material toughness.
研究领域:
材料科学
·
陶瓷工程
·
仿生学
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2019
·
IF 3.078
Qiang Weng,Longyan Duan,Pei Chen,Aiai Gao,Xinbing Chen,Zhongwei An
Modifying the position and numbers of lateral fluorine substituent is a common method to design and adjust the mesophase of liquid crystal compounds. Here, a series of 2-(2,2ʹ-difluoro-4ʹ-alkoxy-1,1ʹ-biphenyl-4-yl)-5-substituted benzoxazole with both non-polar (H, CH3) and polar (NO2) groups (coded as nPF(2)PF(2)Bx) is synthesised and characterised. All of the compounds show a conspicuous inter-ring twist angle of 38° compared with corresponding reference compounds I and II which are calculated by density functional theory method, and it is interesting to note that the final compounds nPF(2)PF(2)Bx show only nematic mesophase during heating or cooling. Meanwhile, the UV-vis absorption bands and photoluminescence emission peaks both display remarkable blue-shifted. The aforementioned results reveal that lateral difluoro substituents play a key role to stable the nematic mesophase by increasing the dihedral angle of biphenyl.
研究领域:
材料科学
·
化学
·
液晶
✓ 已验证
DOI
高影响因子
Journal of Materials Chemistry C
·
2025
·
IF 5.1
Xiaofei Mao,Yixiao Wang,Hao Li,Peilong Zhao,Nan Zhao,Bo Xie,Yuguang Zhou
Graphene, a carbon material with high carrier mobility and low current density, is a promising candidate for the fabrication of flexible sensors. However, its production using traditional methods is complex and expensive, whereas the synthesis of laser-induced graphene (LIG) is eco-friendly and inexpensive under ambient conditions. LIG features a 3D porous structure with localized defects, which is influenced by substrate properties, laser parameters, and processing steps. Herein, the influence of the twist angle between two laser irradiation steps on the porous structure and conductive characteristics of LIG is explored. The results show that the optimal twist angle is 4°, at which the square resistance of LIG is as low as 12.0 Ω sq−1. The change in the conductivity of LIG occurs because the optimal twist angle between the two graphene layers opens the band gap. LIG with a twist angle of 4° is selected to prepare a biosensor and a Hall sensor. It is found that the LIG-based biosensor exhibits a lower detection limit of 8.62 μM when detecting uric acid (UA). Furthermore, the Hall sensitivity of the cross and circular Hall sensors is ∼0.59 and ∼0.64 V (A−1 T−1), respectively. This study supports the application of LIG in flexible sensors and provides some guidelines for further exploration of the 3D structure of LIG.
研究领域:
材料科学
·
纳米技术
·
传感器
·
柔性电子学
·
石墨烯技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）