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Abstract
Introduction
Protocol
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Chimie

一种用于快速和低压彩色调制的电化学胆固醇液晶器件

Published: February 27, 2019
doi:
10.3791/59244
, , , ,
1Department of Chemistry and Biotechnology,The University of Tokyo, 2Department of Chemistry,Tsinghua University, 3RIKEN Center for Emergent Matter Science

Summary

提出了一种用于制造反射式胆固醇液晶显示装置的协议, 该显示装置包含一种能快速、低电压操作的反应还原反应的手性掺杂剂。

Abstract

我们演示了一种制造原型反射显示装置的方法, 该装置包含作为活性成分的胆固醇液晶 (lc)。胆固醇 lc 由一个向列向 lc 4 ‘-五氯-4-氰基联 (5OCB)、氧化还原反应手性掺杂剂 (fcd) 和一个支持电解质 1-乙基-3-甲基咪唑三氟甲烷磺酸酯 (emim-otf) 组成。最重要的组件是fcd。该分子改变其螺旋扭转功率 (htp) 值, 以响应氧化还原反应。因此, lc 混合物中的原位电化学氧化还原反应允许设备根据电刺激改变反射颜色。lc 混合物通过毛细管作用被引入到一个三明治型 ito 玻璃电池中, 该玻璃电池由两个玻璃滑块组成, 带有图案的氧化钛 (ito) 电极, 其中一个被涂上 poly(3,4 乙基二氧氧噻嗪)-共聚(乙烯)掺杂高氯酸盐 (pedot+) 的乙二醇。应用 + 1.5 v 后, 设备的反射颜色在0.4秒内从蓝色 (467 nm) 变为绿色 (485 nm), 随后应用 0 v 使设备恢复到 2.7 s 的原始蓝色。该器件的特点是其最快的电气响应和最低的工作电压在任何以前报告的胆固醇 lc 设备。该器件可为下一代低能耗反射显示器的开发铺平道路。

Introduction

胆固醇液晶 (lc) 是已知的表现出明亮的反射颜色, 因为它们的内部螺旋分子排列1,2,3,4。反射波长由螺旋螺距p和 lc 的平均折射率n ( = np) 决定。这种 lc 可以通过掺杂手性化合物 (手性掺杂物) 到向列 c 产生, 其螺旋音高由方程 p = 1/βm m c 定义, 其中βm 是螺旋扭转力 (htp), c 是摩尔人手性掺杂的分数。基于这一概念, 各种手性掺杂物能够对各种刺激做出反应, 如光5、6、7、8、热9、磁场10和气体11已开发。这些特性可能适用于各种应用, 如传感器12和激光13, 14, 15,以及16、17、18.

最近, 我们开发了第一个反应氧化还原的手性掺杂 fcd (图 1a)19 , 它可以改变其 htp 值, 以响应氧化还原反应。fcd由一个二茂铁单元组成, 它可以经历可逆转的氧化还原反应20,21, 22, 和一个双酚基单元, 已知表现出较高的 htp 值23。在支持电解质存在的情况下, 掺杂fcd的胆固醇 lc 可以在 + 1.5 v 和 0 v 的电压下分别在 2.7 s 内改变其反射颜色, 并在 2.7 s 中恢复其原始颜色。在迄今报告的任何其他胆固醇 lc 设备中, 观察到的该装置的高响应速度和低工作电压都是前所未有的。

胆固醇 lc 的重要应用之一是在反射显示器, 其能耗远远低于传统的 lc 显示器。为此, 胆固醇 lc 应改变其反射颜色与电刺激。然而, 以前的大多数方法都利用了应用的电刺激和宿主 lc 分子之间的电耦合, 这需要超过 40 v24、25、26、27 的高压 ,28。对于电响应手性掺杂剂的使用, 只有几个例子29, 30 包括我们以前的工作31, 这也需要高电压和低响应速度。考虑到这些之前的工作, 我们的 fcd 掺杂胆固醇 lc 设备的性能, 特别是快速的颜色调制速度 (0.4秒) 和低工作电压 (1.5 v), 是一个突破性的成就, 可以大大为下一代反光显示器的发展做出贡献。在这个详细的协议中, 我们演示了原型胆固醇 lc 显示设备的制造工艺和操作过程。

Protocol

1. 胆固醇 lc 混合物的制备 加入84.6 毫克5OCB 和5.922 毫克的fc d 19 (3.1 摩尔% 至 5OCB) 到一个干净的10毫升玻璃瓶。 加入12.9 毫克 emim-otf 和10毫升二氯甲烷 (ch2cl2), 加入一个新的清洁10毫升玻璃瓶, 搅拌均匀。将 emim-otf 溶液的 2.1 ml 转移到5OCB-和fcd 瓶中。轻轻摇晃小瓶, 让所有的成分混合得很好。 …

Representative Results

为含有fcd掺杂的 lc 器件采集了510纳米的照片、透射率谱和时间相关的透射率变化剖面 (3.1 摩尔%)在 emim-otf 存在的情况下的胆固醇 lc (3.0 摩尔%)在37°c 的电压应用周期为0至 + 1.5 v。 含有fcd ( 3.1 摩尔%)、emim-otf (3.0 摩尔%) 的 lc 混合物5OCB 在冷却时表现…

Discussion

在将 + 1.5 v 应用于顶部 ito 电极 (图 1c) 时, fcd会经过氧化反应以产生fcd+。由于fcd+ (101μm-1,图 1b)的螺旋扭转功率低于fcd </s…

Divulgations

The authors have nothing to disclose.

Acknowledgements

我们感谢 riken 紧急物质科学中心的 tajima keisuke 博士进行了宝贵的讨论。这项工作的一部分是在日本教育、文化、体育、科学和技术部的支持下, 在东京大学先进表征纳米技术平台上进行的。这项工作得到了 jsps 科学研究补助金 (s) (18h05260) 的资助, 该赠款资助了 t. a. y. 的 “基于多尺度界面分子科学的创新功能材料”, 感谢 jps 为挑战而提供的赠款探索性研究 (16k14062)。s. t. 感谢 jsps 青年科学家奖学金。

Materials

1-Ethyl-3-methylimidazolium Trifluoromethanesulfonate, 98% TCI E0494
4-Cyano-4'-pentyloxybiphenyl, 98% TCI C1551
Diamond tipped glass cutter AS ONE 6-539-05
Dichloromethane, 99.5% KANTO CHEMICAL 10158-2B HPLC grade
Differential Scanning Calorimeter METTLER TOLEDO DSC 1
Digital microscope  KEYENCE VHX-5000
Extran MA01 Merck 107555
Fully ITO-coated glass plate Costum order, Resistance: ~30Ω
Glass beads Thermo Fisher Scientific 9005 5 ± 0.3 μm in diameter
Hot stage INSTEC mK1000
ITO-patterned glass plate Costum order, Resistance: ~30Ω
Oil rotary vacuum pump SATO VAC TSW-150 Pressure: ~5 Pa
Optical adhesive Noland NOA81
Poly(3,4-ethylenedioxythiophene), bis-poly(ethyleneglycol), lauryl terminated Sigma Aldrich 687316 0.7 wt% (dispersion in nitromethane)
Potentiostat TOHO TECHNICAL RESEARCH PS-08
Rubbing machine EHC MRJ-100S
Spectrophotometer JASCO V-670 UV/VIS/NIR
Spin coater MIKASA 1H-D7
Ultrapure water Merck  Milli-Q Integral 3
Ultrasonic bath AS ONE ASU-2 Power: 40 W
Ultrasonic soldering KURODA TECHNO SUNBONDER USM-IV
UV lamp AS ONE SLUV-4 Power: 4 W
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Tags

Keywords: Cholesteric Liquid CrystalsColor ModulationFcD Chiral DopantElectrochemical DeviceITO GlassPEDOTReflective Displays
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Tokunaga, S., Zeng, M., Itoh, Y., Araoka, F., Aida, T. An Electrochemical Cholesteric Liquid Crystalline Device for Quick and Low-Voltage Color Modulation. J. Vis. Exp. (144), e59244, doi:10.3791/59244 (2019).
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