Effect of H2 SO4 Solution Treatment on Adhesion, Charge Transfer, and Catalytic Performance of Screen-Printed PEDOT:PSS.

Post-treatment was performed for poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) films screen-printed on fluorine-doped tin oxide (FTO) substrates, to improve their charge transfer efficiency. Different H2 SO4 solutions, including concentrated H2 SO4 and H2 SO4 diluted with H2 O or dimethyl sulfoxide (DMSO), were adopted during the post-treatment. The adhesion of the as-treated films was evaluated by adhesive tape peeling tests, the surface morphology and vertical charge transfer from the films to the substrates were investigated by current-sensing atomic force microscopy, and the catalytic activities toward I3 - reduction of PEDOT:PSS films were characterized by electrochemical measurements. It is discovered that selecting proper H2 SO4 solutions is crucial to improve the charge transfer efficiency and catalytic performance while maintaining reliable adhesion of the film on the substrates, with H2 SO4 /DMSO performing best as the solution for post-treatment. A mechanistic explanationis proposed based on different interactions among solution, PEDOT:PSS, and the substrate for various post-treatment solutions.