Materials Advances
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2023
·Vol. 4
·期 9
·2119-2126
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IF 5
Ran Chen,Liang Zhao,Yannanqi Li,Jian Li,Pei Chen,Xinbing Chen,Zhongwei An
A series of tolane liquid crystals terminated by but-3-enyl with high performance (such as high clearing point, low melting point, high birefringence Δn, low viscosity γ1, and broad nematic phase interval) were designed and synthesized in accordance with the phase-only liquid-crystal-on-silicon (LCoS) device requirements for AR displays. The effects of the lateral fluoro-substituent, central alkyne bond, terminal group, and flexible n-alkyl chain on the thermal properties were systematically investigated, and density functional theory (DFT) calculations of molecular conformation and aspect ratio were used to corroborate the experimental results. Further, their properties of phase transition temperature, birefringence, and viscosity were comprehensively evaluated in two typical LC mixtures (001, P02-F). The results indicate that our target compounds can effectively lower the melting point, broaden the working temperature interval, and maintain a high Δn and low γ1 for three LC mixtures. One new LC mixture by employing compound 2TFV as a LC dopant exhibited a high Δn (∼0.26), moderate γ1 and dielectric anisotropy (∼6.3), and broad temperature adaptability (−31.3 °C to 91.3 °C), and achieved 2.08π phase modulation, 5 V operation voltage, and 2.89 ms response time at 40 °C in a reflective LCoS device.
研究领域:
材料科学
·
显示技术
·
光学
✓ 已验证
产品关联
DOI
高影响因子
MOLECULES
·
2023
·Vol. 28
·期 7
·3019
·
IF 4.6
Ran Chen,Zihao Mao,Zhongwei An,Xinbing Chen,Pei Chen
Aromatic heterocyclic liquid crystal (LC) materials have received much attention from LC chemists for their high birefringence and large dielectric anisotropy, yet few have reported their properties in LC mixtures. In this work, a series of fluorinated benzoxazole liquid crystal compounds were synthesized to evaluate their electro-optical properties in high birefringence LC mixtures, with the expectation of further establishing the theoretical basis and experimental evidence for their applications in LC photonics. Firstly, the effects of the lateral fluorine substituent positions on the molecular synthetic yield, mesomorphic and solubility properties were comparatively investigated. Afterwards, we focused on the fluorination effects on the core electro-optical properties, including birefringence, dielectric anisotropy and further investigation of the viscoelastic coefficient of high birefringence LC mixtures. Research results showed that the benzoxazole liquid crystal compounds possess low melting points, wide nematic phase intervals and good solubility by appropriate lateral fluorine substitution, which is beneficial to further improve the electro-optical properties of high birefringence LC mixtures. Meanwhile, the theoretical and experimental results corroborate each other to well reveal the structure–property relationship. This study demonstrates that fluorination would promote promising applications of benzoxazole-terminated liquid crystals in emerging LC optical devices.Keywords:liquid crystal mixture;high birefringence;benzoxazole;large dielectric anisotropy;DFT calculations
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LIQUID CRYSTALS
·
2021
·
IF 0
Ning Xie,Shenghua Du,Ran Chen,Guoqing Liu,Pei Chen,Qiang Weng,Jie Wang,Aiai Gao,Xinbing Chen,Zhongwei An
New benzoxazole-terminated mesogenic compounds containing tolane moiety with high birefringence and large dielectric anisotropy, namely, 2-[4-[2-[4-alkoxyphenyl]ethynyl]-2,6-difluoro-phenyl]-benzoxazole derivatives (nPEDFPBx), were synthesised and investigated. Among them, the ones bearing methyl and nitro substituents at 5-position of benzoxazole moiety exhibit stable mesophase ranges of 30–71°C and 55–81°C during heating and cooling processes, respectively, while the non-substituted compounds exhibit no mesophase except the ones with long terminal alkoxy chain (n = 10, 12). Birefringence of nPEDFPBx is obtained from DFT theoretical calculation (0.446–0.583) and experimental measurement (0.395–0.499), respectively, where high birefringence is ascribed to their large π-conjugated molecule composed of benzene ring, acetylene linkage and benzoxazole moiety. Meanwhile, it is found that nPEDFPBx displays large dielectric anisotropy because of their high dipole moment. As an example, the compound 5PEDFPBM is doped into the liquid crystalline mixture as an additive, the properties of the resulting mixture, such as birefringence, dielectric anisotropy, clearing point and response time, are improved obviously, indicating high potential application for liquid crystalline mixture.
研究领域:
材料科学
·
化学
✓ 已验证
DOI
Journal of the American Chemical Society
·
2023
·
IF 15
Jia-Hang Wu,Chun-Li Hu,Ting-Kun Jiang,Jiang-Gao Mao,Fang Kong
An unusual O/F ordered d0 transition metal fluoroantimonite, namely, K2SbMoO2F7, has been created by the cationic size effect of alkali metals. It features the largest birefringence of 0.220@550 nm among inorganic antimonites with a halogen element, which is an order of magnitude larger than the disordered A2SbMoO2F7 (A = Rb, Cs). These three new compounds exhibit two different structures, although all of the structures were made of [SbMoO2F7]2– chains formed by SbF5 square pyramids and MoO2F4 octahedrons. A transparent single crystal of K2SbMoO2F7 with dimensions of 7.0 × 5.0 × 1.0 mm3 has been successfully grown by the aqueous solution volatilization method. The UV–vis–MIR transmission spectrum showed that K2SbMoO2F7 can display excellent transmittance in the range of 0.5–5.0 μm and 6.0–9.8 μm, indicating its application potential as a birefringent material in the mid infrared band. This work offers a fresh approach to the design and synthesis of mid infrared birefringent materials.
研究领域:
材料科学
·
晶体学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LIQUID CRYSTALS
·
2023
·
IF 2.2
Jiaxing Tang,Chenhe Yao,Zhongwei An,Ran Chen,Zihao Mao,Xinbing Chen,Pei Chen
A series of liquid crystals containing one n-propyl/n-propoxy, lateral fluorine substituent, a tolane mesophase unit, and a 2,2-difluorovinyl terminal group were designed and synthesised. Their chemical structures were characterised and confirmed by nuclear magnetic resonance (NMR), mass spectrometry and Fourier transform infrared spectrometry (FTIR) instruments. Meanwhile, the position and number effects of lateral fluorine substituents on the thermal, mesomorphic, and electro-optical properties of these compounds were explored. Furthermore, density functional theory (DFT) calculations of molecular conformation, polarisability components and dipole moment were utilised to correlate the experimental results. Research results show that the 2,2-difluorovinyl-terminated liquid crystal compounds possess excellent properties of low melting point, wide nematic-phase temperature interval, high birefringence, large dielectric anisotropy and low rotational viscosity. This molecular splicing strategy is an effective method to balance the trade-offs between high birefringence, large dielectric anisotropy, and low viscosity in nematic liquid crystals.
研究领域:
材料科学
·
化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2023
·
IF 6
Chenhe Yao,Jiaxing Tang,Ran Chen,Zihao Mao,Xinbing Chen,Pei Chen,Zhongwei An
A series of liquid crystals (LCs) containing bis-tolane, lateral fluorine substituents and 2,2-difluorovinyloxyl group were designed and synthesized. Their LC phase behavior, birefringence, dielectric anisotropy and viscosity properties were discussed by comparing with previously reported LCs with high birefringence and large electrical anisotropy. Meanwhile, the effects of lateral fluorine numbers on the melting point, birefringence and dielectric anisotropy of these LCs were explored, and density functional theory (DFT) calculations of molecular conformation and polarizability were used to correlate the experimental results. Research results indicated that the 2,2-difluorovinyloxyl terminal group decreased the melting points of these LCs, and these LCs showed relatively low melting point (<113.7 ℃), broad nematic-phase temperature interval, high birefringence (>0.4), and large dielectric anisotropy (35.87). Furthermore, performance in high birefringence LC mixture demonstrated that they could effectively improve the birefringence and dielectric anisotropy, and maintain low viscosity, which is expected to possess widespread applications in fast response LC optical devices.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
LIQUID CRYSTALS
·
2023
·
IF 2.2
Ran Chen,Zihao Mao,Jiaxing Tang,Xinbing Chen,Pei Chen,Zhongwei An
Liquid crystal (LC) mixtures with high birefringence (∆n) and low rotational viscosity play an essential role for fast-response LC devices. However, high birefringence and low rotational viscosity are a pair of contradictory performance parameters. In this work, two high-∆n LC diluters are proposed to achieve a fine balance between them. These two terminal olefin diluters containing a rigid biphenyl core with a lateral fluorine substituent, a buty-3-enyl terminal group and a flexible n-alkyl chain were designed and synthesised through classical organic synthetic reactions. Meanwhile, their comprehensive properties were further evaluated in a LC mixture P02-F containing fluoro-tolane and a LC mixture P12-ISO containing isothiocyano-tolane. The results show that the biphenyl diluters 2BBF2V and 3BFB2V could effectively decrease the Tm of LC mixture P12-ISO to below −25°C, while maintain high ∆n and large Δε, which are suitable for the high-∆n LC mixtures containing isothiocyano-tolane. Furthermore, DFT calculations of molecular conformation and polarisability components were utilised to correlate the experimental findings.
研究领域:
材料科学
·
化学
·
液晶技术
·
有机合成
✓ 已验证
DOI
高影响因子
INORGANIC CHEMISTRY
·
2025
·
IF 4.7
Jiale Xue,Shuyao Wang,Xiande Peng,Zhengyan Lin,Xuehua Dong,Liling Cao,Ling Huang,Guohong Zou
We present two novel antimony(III)-based tellurite sulfate crystals, Sb2(TeO3)(SO4)2-P1̅ (I) and Sb2(TeO3)(SO4)2-P21/c (II), synthesized using a dual lone pair strategy that incorporates Sb3+ and Te4+ ions into a sulfate framework. This approach significantly enhances the birefringence of these compounds, with values of 0.11 and 0.10 at 546 nm, respectively, surpassing those of many previously reported mixed alkali metal/alkaline earth metal sulfates and tellurites. Both compounds also exhibit excellent UV transparency with cutoff edges at 292 and 294 nm, making them promising candidates for short-wave UV optical applications. Structural and theoretical analyses reveal that the enhanced birefringence arises from the synergistic effects of the stereochemically active lone pairs of Sb3+ and Te4+, which contribute to the optical anisotropy. This work highlights the potential of dual SCALP elements in improving the optical properties of sulfate-based crystals and provides new insights into designing high-performance optical materials with tailored properties for advanced UV technologies.
研究领域:
材料科学
·
光学材料
·
无机化学
·
晶体工程
·
光子学
✓ 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）