物理化学学报 >> 2016, Vol. 32 >> Issue (9): 2377-2382.doi: 10.3866/PKU.WHXB201605242

论文 上一篇    

ZIF-8对向列相液晶电-光性能的提升

许丽红,赵东宇*(),李阳,郭林*()   

  • 收稿日期:2016-03-31 发布日期:2016-09-08
  • 通讯作者: 赵东宇,郭林 E-mail:zhaodongyu@buaa.edu.cn;guolin@buaa.edu.cn
  • 基金资助:
    国家自然科学基金(51203005);高等学校博士学科点专项科研基金(20121102120045)

Improvement of the Electro-Optical Properties of Nematic Liquid Crystals by Doping with ZIF-8 Materials

Li-Hong XU,Dong-Yu ZHAO*(),Yang LI,Lin GUO*()   

  • Received:2016-03-31 Published:2016-09-08
  • Contact: Dong-Yu ZHAO,Lin GUO E-mail:zhaodongyu@buaa.edu.cn;guolin@buaa.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(51203005);Specialized Research Fund for the Doctoral Program of Higher Education of China(20121102120045)

摘要:

ZIF-8(沸石咪唑酯骨架结构材料)是一种金属有机物骨架结构材料,因其极高的比表面积、出色的热稳定性而被广泛应用于各种性质研究中。ZIF-8通过传统的水热法在甲醇溶液中合成,其颗粒尺寸约为250nm,形貌为菱形十二面体。研究发现,合成的ZIF-8材料具有良好的热稳定性及相当大的比表面积。将其掺杂进液晶中会增强液晶的电-光性能,增强效果与掺杂浓度有关。在向列相液晶4-氰基-4'-戊基联苯(5CB)中,ZIF-8可以吸附杂质离子,抑制屏蔽效应,最终使液晶驱动电压降低,响应加快。在掺杂浓度为0.05%(w,质量分数)时,液晶体系的电-光性能改善最明显,阈值电压(Vth)最小达到0.92 V,饱和电压(Vsat)达到1.31 V,响应时间仅为10.04 ms。而当掺杂浓度大于0.05%(w)时,ZIF-8在液晶盒中发生团聚,影响液晶分子的有序排布,同时吸附杂质离子减少,不利于液晶电-光性能的改善。

关键词: ZIF-8, 向列相液晶, 电-光性能, 阈值电压, 响应时间, 屏蔽效应

Abstract:

ZIF-8 (zeolitic imidazolate framework-8), a kind of metal-organic framework material, is one of the most important energy materials and widely used in various fields because of its high specific surface area and excellent thermal stability. In this research, we synthesized ZIF-8 by the traditional hydrothermal synthesis method in a purely methanol system. The obtained particles were~250 nm in diameter with a rhombic dodecahedron morphology. Moreover, the prepared ZIF-8 materials exhibited good thermal stability and a large surface area. We also found that the rhombic dodecahedral ZIF-8 enhanced the electro-optical (E-O) properties of nematic liquid crystal (N-LC) depending on the ZIF-8 doping concentrations. ZIF-8 in N-LC cells adsorbs ionic impurities and suppresses the screen effect, leading to a lower driving voltage and faster response time. At a ZIF-8 doping concentration of 0.05%(w, mass fraction), the N-LC cells showed the best E-O properties, including the lowest threshold voltage (Vth) of 0.92 V, the lowest saturation voltage (Vsat) of 1.31 V, and a short response time of 10.04 ms. However, above a doping concentration of 0.05%(w) ZIF-8 aggregated in N-LC cells, affecting the arrangement of the LC molecules and trapping less impurity ions, which deteriorated the E-O properties of N-LC.

Key words: ZIF-8, Nematic liquid crystal, Electro-optical property, Threshold voltage, Response time, Screen effect

MSC2000: 

  • O643