Stability of poly(3,4-ethylenedioxythiophene) thin films prepared by vapor phase polymerization

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• 作者：Jö ; rgen Metsik^a ; ^{jorgen.metsik@ut.ee" class="auth_mail" title="E-mail the corresponding author} ; Martin Timusk^b ; Tanel Kä ; ä ; mbre^b ; Hugo Mä ; ndar^b ; Madis Umalas^b ; Agnes Kuus^b ; Laurits Puust^b ; Kathriin Utt^b ; Ilmo Sildos^b ; Uno Mä ; eorg^a
• 关键词：Conductive polymers ; Poly(3 ; 4-ethylenedioxythiophene) ; Thin films ; Polymer aging ; Vapor phase polymerization
• 刊名：Polymer Degradation and Stability
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：126
• 期：Complete
• 页码：170-178
• 全文大小：1513 K

文摘

Sufficient stability of conductive polymers is crucial for allowing widespread application of these materials. Poly(3,4-ethylenedioxythiophene) (PEDOT) has a relatively high conductivity and transparency among conductive polymers. In this study, the stability of PEDOT thin films prepared by vapor phase polymerization was investigated at elevated temperatures in air (100–140 °C) and in argon (140 °C) and at room temperature in various environments. Ultraviolet light, water vapor and vacuum exerted a detrimental effect on the stability of PEDOT films at room temperature. Slow decay of conductivity was unavoidable even under inert gas at room temperature, while decay in air and in inert gas environment was comparable at 140 °C. Characteristic changes in the ultraviolet-visible-near infrared absorbance spectra appeared in all the aged samples. The chemical composition was investigated by using Raman spectroscopy and X-ray photoelectron spectroscopy. The structure of the films was determined by grazing incidence X-ray diffraction. Temperature dependences of resistance were measured for thermally aged and untreated films, demonstrating that during aging a transition occurs from critical to insulating behavior.