乙腈对环己烷单体溶液中沉降聚合聚3,4-乙撑二氧噻吩涂层结构与光电性能的影响

Effect of Acetonitrile on Molecular Structures and Optoelectronic Properties of PEDOT Coatings Synthesized in Acetonitrile/Cyclohexane Solutions by Liquid Phase Depositional Polymerization

为利用溶剂化效应来优化液相沉降聚合聚3,4-乙撑二氧噻吩(PEDOT)的结构和光电性能,将吸附Fe(OTs)3的聚对苯二甲酸乙二醇酯(PET)膜悬于含乙腈的EDOT环己烷溶液中,于60℃原位合成PEDOT涂层。以紫外-可见吸收光谱、X射线光电子能谱分析所合成PEDOT的共轭链结构和掺杂度,以四探针测量表面电阻,研究乙腈含量对合成PEDOT结构与性能的影响。当乙腈体积分数为0.05%时,添加的乙腈能抑制短共轭链的生成,提高掺杂度,在降低表面电阻的同时,改善透光率。乙腈体积分数在0.24%以内时,PEDOT的导电性随乙腈体积分数的上升而增加。当乙腈体积分数超过0.7%时,PEDOT中短共轭链数目增加,光电性能下降。当乙腈体积分数为8%时,由于吸附的Fe(OTs)_3溶解太快,无法在PET表面合成导电PEDOT膜。乙腈体积分数为0.24%时,获得的PEDOT膜的表面电阻可达174Ω,透光率80%,粘附力为5B级。

To understand the effect of solvent on molecular structures and optoelectronic properties of poly（3,4- ethylenedioxythiophene） （PEDOT） synthesized in EDOT solution by liquid phase depositional polymerization and explore alternative for indium tin oxid（ITO） flexible transparent conductive film, polyethylene terephthalate （PET） film with adsorbed Fe（OTs）3 was suspended in EDOT acetonitrile/cyclohexane solutions and PEDOT coating was synthesized on PET film in situ at 60 Z;. The synthesized PEDOT coatings were characterized by FT-IR, UV-vis and XPS spectroscopes and the sheet resistances were measured by four-point probe. The effect of aeetonitrile content on molecular structures and optoelectronic properties was investigated. In EDOT solution, acetonitrile increases the absorbanee of EDOT and exhibit strong solvating ability. The conjugative defects, doping levels and optoelectronic properties of synthesized PEDOT coating vary with acetonitrile content. At volume fraction of 0.05%, added aeetonitrile depresses the short conjugative chains and enhances the doping level, thereby, reduces the sheet resistance and enhances the transmittance. The sheet resistance decreases with the acetonitrile volume fraction till 0.24 %. As the acetonitrile content is above 0.7%, the short conjugative chains increases and sheet resistance rebounds. In EIX）T solution with 8 % of acetonitrile, the adsorbed Fe（OTs）3 would escape from the stagnant layer and is not able to synthesize PEDOT coating on PET film. At the acetonitrile volume fraction of 0.24%, a PEDOT/PET film with the sheet resistance 174% and transmittance 80 % could be prepared by liquid phase depositional polymerization in EDOT acetonitrile/cyclohexane solution.