Charge Transport Properties of poly(3,4-ethylenedioxythiophene)/poly(styrene sulfonate): A Tera-Hertz Study

• Main Author: 陳慶銘
• Other Authors: Tsong-Ru Tsai
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/31803155333956699927

碩士 === 國立臺灣海洋大學 === 光電科學研究所 === 97 === In this article, we studied transport properties of poly (3,4-ethylenedioxythiophene)/ poly (styrene sulfonate) (PEDOT:PSS) conducting polymer films by non-contact terahertz time domain spectroscopy (THz-TDS). The PEDOT:PSS(1:2.5)、(1:6)、(1:20) films were formed by dropping cast on high resistance silicon substrate. The film thickness is around 15μm. The laser source of the THz-TDS is 1-kHz, 300-μJ, 800-nm, 120-fs laser pulse generated by regenerated Ti-sapphire amplifier. 90% of the laser energy is used to generate terahertz by optical rectification in thickness 1mm (110) ZnTe crystal. The detection of the terahertz is to utilize EO sampling in another thickness 1mm (110) ZnTe crystal. All measurements are performed inside a nitrogen gas purged enclosure (<1% relative humidity). The absorption and dispersion of PEDOT:PSS films from 0.25 to 2.5 THz region are obtained by analyzing the transmission terahertz signal with and without PEDOT:PSS films on silicon substrate. The dielectric and conductivity properties of PEDOT:PSS films are further obtained over this frequency range. The DC conductivity obtained from extrapolation of the measurement matches the DC electrical measurement result. The real part of conductivity shows that it increases with growing frequency. This conductivity characteristic of the PEDOT:PSS films can not be fit by the simple Drude model but can be fit by the localization-modified Drude model.