Significant conductivity enhancement of conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) films through a treatment with organic carboxylic acids and inorganic acids.
Significant conductivity enhancement of conductive poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) films through a treatment with organic carboxylic acids and inorganic acids.
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DOI：
10.1021/am900708x
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发表时间：
2010-02
影响因子：
9.5
通讯作者：
Yijie Xia;Jianyong Ouyang
中科院分区：
文献类型：
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作者：
Yijie Xia;Jianyong Ouyang
经有机酸、丙酸、丁酸、草酸、亚硫酸和盐酸等有机和无机酸处理后，透明导电的聚(3，4-乙二氧基噻吩基)：聚苯乙烯磺酸(PEDOT：PSS)薄膜的导电性显著提高。电导率可从0.2提高到200多S厘米(-1)，即提高1000多倍。电导率的提高取决于酸的结构和处理过程中的实验条件，如酸的浓度和温度。在120~160℃温度范围内，PEDOT：PSS薄膜经高浓度酸溶液处理后，电阻迅速下降，而经低浓度酸溶液处理后，电阻逐渐增大，而后又逐渐降低。通过不同的化学和物理表征，研究了电导率提高的机理。电导率与温度的关系表明，经过酸处理后的高导电性PEDOT：PSS薄膜中，PEDOT链间电荷跃迁的势垒降低。紫外-可见-近红外(UV-Vis-NIR)吸收光谱、X-射线光电子能谱(XPS)和扫描电子显微镜(SEM)表明，酸处理后PEDOT：PSS薄膜中的聚苯乙烯磺酸(PSSH)链丢失，原子力显微镜(AFM)表明聚合物链的构象发生了变化。因此，电导率的提高归因于PEDOT：PSS膜上PSSH链的损失和酸引起的PEDOT链的构象变化。
Significant conductivity enhancement was observed on transparent and conductive poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) films after a treatment with organic and inorganic acids, including acetic acid, propionic acid, butyric acid, oxalic acid, sulfurous acid, and hydrochloric acid. The conductivity could be enhanced from 0.2 to over 200 S cm(-1), that is, by a factor of more than 1000. The conductivity enhancement was dependent on the structure of the acids and the experimental conditions during the treatment, such as the acid concentration and the temperature. The optimal temperature was in the range of 120 to 160 degrees C. The resistance dropped rapidly when a PEDOT:PSS film was treated with acid solution of high concentration, whereas it gradually increased and then decreased when it was treated with an acid solution of low concentration. The mechanism for this conductivity enhancement was studied by various chemical and physical characterizations. The temperature dependence of conductivity indicates that the energy barrier for charge hopping among the PEDOT chains become lower in the highly conductive PEDOT:PSS film after the acid treatment. The ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectroscopy, the X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) indicate the loss of polystyrene sulfonic acid (PSSH) chains from the PEDOT:PSS film after the acid treatment, and the atomic force microscopy (AFM) suggest conformational change of the polymer chains. Therefore, the conductivity enhancement is attributed to the loss of PSSH chains from the PEDOT:PSS film and the conformational change of the PEDOT chains, which are induced by the acids.