A Graphene-Based Polymer-Dispersed Liquid Crystal Device Enabled through a Water-Induced Interface Cleaning Process

Eun Mi Kim; Su Jin Kim; Go Bong Choi; Jaegeun Lee; Min Mo Koo; Jaewoong Kim; Young Won Kim; Jongho Lee; Jin Hyeok Kim; Tae Hoon Seo

doi:10.3390/nano13162309

A Graphene-Based Polymer-Dispersed Liquid Crystal Device Enabled through a Water-Induced Interface Cleaning Process

Nanomaterials (Basel). 2023 Aug 11;13(16):2309. doi: 10.3390/nano13162309.

Authors

Eun Mi Kim^{1

2}, Su Jin Kim^{1

2}, Go Bong Choi³, Jaegeun Lee⁴, Min Mo Koo⁵, Jaewoong Kim⁵, Young Won Kim¹, Jongho Lee¹, Jin Hyeok Kim^{2

6}, Tae Hoon Seo¹

Affiliations

¹ Green Energy and Nano Technology & R&D Group, Korea Institute of Industrial Technology (KITECH), Gwangju 61012, Republic of Korea.
² School of Materials Science & Engineering, Chonnam National University, Gwangju 61186, Republic of Korea.
³ Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea.
⁴ School of Chemical Engineering, Pusan National University, Busan 46261, Republic of Korea.
⁵ Automotive Materials & Components R&D Group, Korea Institute of Industrial Technology (KITECH), Gwangju 61012, Republic of Korea.
⁶ Optoelectronic Convergence Research Center, Department of Materials Science and Engineering, Chonnam National University, Gwangju 61186, Republic of Korea.

Abstract

We report the use of four-layer graphene (4LG) as a highly reliable transparent conductive electrode (TCE) for polymer-dispersed liquid crystal (PDLC)-based smart window devices. The adhesion between 4LG and the substrate was successfully improved through a water-induced interface-cleaning (WIIC) process. We compared the performance of a device with a WIIC-processed 4LG electrode with that of devices with a conventional indium tin oxide (ITO) electrode and a 4LG electrode without a WIIC. With the application of the WIIC process, the PDLC smart window with a 4LG electrode exhibited reduced turn-on voltage and haze compared to 4LG without the WIIC process and characteristics comparable to those of the ITO electrode. The WIIC-processed 4LG electrode demonstrated enhanced electrical properties and better optical performance, leading to improved device efficiency and reliability. Furthermore, our study revealed that the WIIC process not only improved the adhesion between 4LG and the substrate but also enhanced the compatibility and interfacial interactions, resulting in the superior performance of the smart window device. These findings suggest that 4LG with WIIC holds great promise as a transparent conductive electrode for flexible smart windows, offering a cost-effective and efficient alternative to conventional ITO electrodes.

Keywords: adhesion; four-layer graphene; polymer-dispersed liquid crystal; smart window; water-induced interface cleaning.

Grants and funding

This study was conducted with the support of the Korea Institute of Industrial Technology under the Development of Core Technologies for Smart Mobility (KITECH JA-23-0011) project. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Education, Science, and Technology (NRF-2022R1F1A1074422), and by the Korea Institute of Marine Science and Technology Promotion (KIMST), funded by the Ministry of Oceans and Fisheries, Korea (20200599).