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-乙撑二氧噻吩):聚(苯乙烯磺酸盐)（Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), 简称PEDOT:PSS）是目前应用最为广泛的透明导电聚合物，被广泛应用于各类功能有机器件之中。然而，其在制备高导电电极领域的潜力仍未得到充分发掘。本研究旨在填补二甲基亚砜（dimethyl sulfoxide, DMSO）掺杂PEDOT:PSS薄膜后处理相关的现有研究空白。本研究针对盖玻片基底上经二甲基亚砜掺杂的PEDOT:PSS多层膜，系统考察了未处理与经硫酸处理样品的表面形貌、光学与电学性能。研究结果表明，短时硫酸处理可有效改善该透明导电薄膜的光电性能，并使其表面更加平整。电导率提升幅度超过30%，这一现象可归因于掺杂水平的提升、过量PSS的去除以及共轭PEDOT分子链形态的相应改变。此外，硫酸处理还可使透射光谱更为平滑，并小幅提升光学透光率。综上，硫酸后处理可作为一种简便且低成本的辅助掺杂手段，用于经二甲基亚砜掺杂的PEDOT:PSS薄膜，以制备性能更优异的透明电极。