Solution-Processed Poly(3,4-ethylenedioxythiophene) Thin Films as Transparent Conductors: Effect of p-Toluenesulfonic Acid in Dimethyl Sulfoxide

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• 作者：Smita Mukherjee ; Rekha Singh ; Sreelekha Gopinathan ; Sengottaiyan Murugan ; Suhas Gawali ; Biswajit Saha ; Jayeeta Biswas ; Saurabh Lodha ; Anil Kumar
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：October 22, 2014
• 年：2014
• 卷：6
• 期：20
• 页码：17792-17803
• 全文大小：612K
• ISSN：1944-8252

文摘

Conductivity enhancement of thin transparent films based on poly(3,4-ethylenedioxythiophene)鈥損oly(styrenesulfonate) (PEDOT鈥揚SS) by a solution-processed route involving mixture of an organic acid and organic solvent is reported. The combined effect of p-toluenesulfonic acid and dimethyl sulfoxide on spin-coated films of PEDOT鈥揚SS on glass substrates, prepared from its commercially available aqueous dispersion, was found to increase the conductivity of the PEDOT鈥揚SS film to 鈭?500 S路cm^鈥? with a high transparency of at least 94%. Apart from conductivity and transparency measurements, the films were characterized by Raman, infrared, and X-ray photoelectron spectroscopy along with atomic force microscopy and secondary ion mass spectrometry. Combined results showed that the conductivity enhancement was due to doping, rearrangement of PEDOT particles owing to phase separation, and removal of PSS matrix throughout the depth of the film. The temperature dependence of the resistance for the treated films was found to be in accordance with one-dimensional variable range hopping, showing that treatment is effective in reducing energy barrier for interchain and interdomain charge hopping. Moreover, the treatment was found to be compatible with flexible poly(ethylene terephthalate) (PET) substrates as well. Apart from being potential candidates to replace inorganic transparent conducting oxide materials, the films exhibited stand-alone catalytic activity toward I鈥?/sup>/I₃鈥?/sup> redox couple as well and successfully replaced platinum and fluorinated tin oxide as counter electrode in dye-sensitized solar cells.

Keywords:

PEDOT鈭扨SS; transparent conducting polymer; conductivity enhancement; organic acid treatment; dye-sensitized solar cell