Twisted Nematic Liquid-Crystal-Based Terahertz Phase Shifter using Pristine PEDOT: PSS Transparent Conducting Electrodes
| Title: | Twisted Nematic Liquid-Crystal-Based Terahertz Phase Shifter using Pristine PEDOT: PSS Transparent Conducting Electrodes |
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| Authors: | Anup Kumar Sahoo, Chan-Shan Yang, Chun-Ling Yen, Hung-Chun Lin, Yu-Jen Wang, Yi-Hsin Lin, Osamu Wada, Ci-Ling Pan |
| Source: | Applied Sciences, Vol 9, Iss 4, p 761 (2019) |
| Publisher Information: | MDPI AG, 2019. |
| Publication Year: | 2019 |
| Collection: | LCC:Technology LCC:Engineering (General). Civil engineering (General) LCC:Biology (General) LCC:Physics LCC:Chemistry |
| Subject Terms: | liquid crystals, LC, twisted nematic, TN, phase shifter, PEDOT: PSS, transparent conducting electrode, TCE, terahertz, THz, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999 |
| More Details: | For this study, we demonstrated three different types of twisted nematic (TN) liquid crystal (LC) terahertz (THz) phase shifters using pristine poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) thin films as transparent conducting electrodes (TCEs). The transmittance of spin-coated pristine PEDOT: PSS thin film was as high as 92% in the frequency range of 0.2–1.2 THz. This is among the highest reported. Several TN-LC cells were constructed in a comparative study, which confirmed the reliability of pristine PEDOT: PSS as a TCE layer for THz phase shifter applications. The highest phase shift, required root-mean-square (RMS) driving voltage, and threshold voltage achieved by devices tested were 95.2° at 1 THz, 7.2 VRMS, and 0.5 VRMS, respectively. The thickness of the LC layer for the phase shifter was 250 µm, approximately half as thick as previous designs. In addition, the pristine PEDOT: PSS-based TN-LC phase shifter exhibited a figure-of-merit (FOM) value of approximately 6.65 degree·dB−1·V−1. This compared favorably with previously reported homogeneously aligned phase shifters with an FOM of 2.19 degree·dB−1·V−1. Our results indicated that a twisted nematic LC cell with pristine PEDOT: PSS thin films as electrodes is a good combination for a THz phase shifter and wave plates as well as other LC-based THz devices. |
| Document Type: | article |
| File Description: | electronic resource |
| Language: | English |
| ISSN: | 2076-3417 |
| Relation: | https://www.mdpi.com/2076-3417/9/4/761; https://doaj.org/toc/2076-3417 |
| DOI: | 10.3390/app9040761 |
| Access URL: | https://doaj.org/article/0f8a297685d9455e8babbd8574ae9c75 |
| Accession Number: | edsdoj.0f8a297685d9455e8babbd8574ae9c75 |
| Database: | Directory of Open Access Journals |
| ISSN: | 20763417 |
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| DOI: | 10.3390/app9040761 |
| Published in: | Applied Sciences |
| Language: | English |