Structure and Properties of Dual-doped PEDOT:PSS Multilayer Films

Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most successful transparent conductive polymer widely used in functional organic devices. However, its potential in fabrication of highly conductive electrodes still has not been fully explored. This paper is an attempt to fill the existing gap of knowledge on possible post-treatments of dimethyl sulfoxide (DMSO)-doped PEDOT:PSS thin films. In the present study, surface morphology, optical and electrical properties of untreated and sulfuric acid treated DMSO-doped PEDOT:PSS multilayers on the glass coverslip substrates are examined. It is demonstrated that short-time sulfuric acid treatment enhances electrical and optical properties, and smoothens surface of the transparent conductive films. Enhancement of electrical conductivity by more than 30 % can be associated with increase in doping level, removal of excess PSS and accompanied shape alterations of the conjugated PEDOT chains. Acid treatment also results in smoother transmittance spectra and a slight improvement of optical transparency. Hence, sulfuric acid post-treatment can be considered as a simple and inexpensive technique for the complementary doping of DMSO-doped PEDOT:PSS films with the aim to develop the more effective transparent electrodes.

聚(3,4-亚乙二氧基噻吩):聚(苯乙烯磺酸盐)（PEDOT:PSS）是目前应用最为广泛的功能性有机器件用透明导电聚合物。然而，其在制备高导电电极方面的潜力仍未得到充分挖掘。本研究旨在填补二甲基亚砜（DMSO）掺杂PEDOT:PSS薄膜后处理相关的现有知识空白。本工作以盖玻片为基底，对未处理及经硫酸处理的DMSO掺杂PEDOT:PSS多层膜的表面形貌、光学与电学性能进行了系统表征。研究结果表明，短时硫酸处理可提升该透明导电薄膜的电学与光学性能，并使表面更为平整。电导率提升超30%，可归因于掺杂水平的提高、过量PSS的去除以及共轭PEDOT链伴随发生的构象改变。酸处理还可使透光光谱更为平整，并小幅提升光学透过率。因此，硫酸后处理可作为一种简单低成本的辅助掺杂手段，用于DMSO掺杂PEDOT:PSS薄膜的改性，以开发性能更优异的透明电极。