Electronic Functions in Liquid-Crystalline Nanostructures with High Polarization
- PDF / 606,525 Bytes
- 8 Pages / 432 x 648 pts Page_size
- 63 Downloads / 161 Views
MRS Advances © 2019 Materials Research Society DOI: 10.1557/adv.2019.247
Electronic Functions in Liquid-Crystalline Nanostructures with High Polarization Masahiro Funahashi1,2 1 Program of Advanced Materials Science, Faculty of Engineering and Design, Kagawa University, 221720 Hayashi-cho, Takamatsu, Kagawa 761-0396, Japan
2 Health Research Institute, National Institute of Advanced Industrial Science and Technology, 2217-14 Hayashi-cho, Takamatsu, Kagawa 761-0395, Japan
Abstract
Multifunctionality was created by coupling an electronic charge carrier transport with ionic conductivity or ferroelectricity in polarized liquid crystal phases. Liquid-crystalline perylene bisimide derivatives bearing cyclotetrasiloxane rings and triethylene oxide chains formed nanosegregated columnar structures which could conduct ions as well as electrons. The spincoated thin films could be insolubilized by the exposure on acid vapors and display electrochromism. Phenylterthiophene derivatives bearing a chiral alkyl side chain exhibited a ferroelectric phase, in which a photovoltaic effect was caused by the interaction between photogenerated charge carriers with the internal electric field formed by the spontaneous polarization of the ferroelectric phase.
INTRODUCTION: Liquid crystals comprised of extended π-conjugated units including liquid crystalline semiconductors are promising materials suitable for printed electronics because of their high carrier mobilities and good processability [1-5]. Since liquid crystal phases can be regarded as soft fields for integration of molecular functionality, to couple physical and chemical processes in the liquid crystal phases has a potential for the creation of new functional materials. Molecules consisting of incompatible units usually form nanosegregated structures. Imidazolium derivatives bearing long alkyl chains exhibit columnar phases, in which one-dimensional aggregates of ionic moieties surrounded by hydrophobic alkyl chains and one-dimensional ionic conductivity was observed in the columnar phases [6]. Nanosegregated π-conjugated liquid crystals can be
1733
Downloaded from https://www.cambridge.org/core. University of California, Santa Cruz, on 22 Dec 2019 at 06:10:53, subject to the Cambridge Core terms of use, available at https://www.cambridge.org/core/terms. https://doi.org/10.1557/adv.2019.247
multi-functional soft materials in which an electronic function interacts with optic, ionic, ferroelectric, and electrochemical activities [7-9]. In this study, electrically polarized structures are constructed in the nanosegregated liquid crystal phases. We demonstrate to couple the electronic function with the ionic transport in the nanosegregated columnar structures and the ferroelectricity in the chiral smectic C (SmC*) phase, respectively. Efficient ionic transport makes it possible to form soft structures with high electric polarization which interact with πconjugated systems [10]. Electrochromism and interstitial doping are achieved in the nanosegregated columnar phases [11]. In
Data Loading...
