The Investigation of High Quality PEDOT:PSS Film by Multilayer-Processing and Acid Treatment

Abstract

Abstract:In this study, we have investigated the performance of multilayer films of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) treated with one of the perfluorinated carboxylic acids, named trifluoroacetic acid (TFA). According to the increased density of the PEDOT chain under unit area conditions, the sheet resistance (R sq ) has improved from 300 to 65 Ω/sq through additional processing of PEDOT:PSS from single layer to multilayer. After the further treatment with TFA, however, the R sq of the multilayer PEDOT:PSS was enhanced to 45 Ω/sq, leading to the decline of film thickness from 400 to 270 nm. Both conductivity and work function based on X-ray photoelectron spectroscopy results have built a breakthrough by double-processing because of the higher density of conductive PEDOT chains and the increase of 0.4 eV alternatives to typical indium tin oxide substrate, respectively. This improvement is contributed to the development of more effective transparent electrodes.

Computational microscopy study of the granular structure and pH dependence of PEDOT:PSS

“…The morphology models of PEDOT:PSS suggested in experimental studies vary from a formation of ellipsoidal PEDOT micelles with PSS shells 43,50 to PEDOT islands in PSS shells and a free PSS region, 58 random coils of PEDOT and PSS, 27,37,54,56,60 a PEDOT rich core and a PSS rich shell, 27,48,52,53,61 a pancakelike morphology, 14,47,48 PEDOT-and PSS-rich regions, 46 and a uniform distribution of PEDOT along PSS chains in solution. 40 Experimentally, pH is typically controlled by acid treatment. It can be performed in different ways, by dropping acid on the films, 34,35 soaking the film into acid, 37 by acid vapor 36 or by adding acid to aqueous solution.…”

“…22,23 While the details of the methods and corresponding experimental control of pH can be different, all these methods increase the concentration of H + in the blend, which leads to a higher concentration of PSSH as modelled by our simulations. Also there are different experimental models to explain the results of the acidic treatment of PEDOT:PSS, e.g., a coil to a linear/expanded-coil conformation, 36,37,56 continuous network to non-continuous clusters, 25 phase separation between PEDOT and PSS, 40 conformational change of the PEDOT chains and loss of PSS-H, 34 and formation of highly ordered and densely packed PEDOT:PSS. 35 Our present theoretical results provide a detailed atomistic picture for the morphology of PEDOT:PSS solution and dried films at different pH and demonstrate how the variation of pH can lead to different observed morphologies of PEDOT:PSS films.…”

“…35 X-ray photoelectron spectroscopy also shows the change in the chemical environment of PSS and reducing the PSS weight ratio after acidic treatment. 22,[38][39][40][41] The morphology of PEDOT:PSS shows a very complex character and depends on various factors as outlined above. It should be stressed however that that are several major features that are repeatedly reported in many studies.…”

“…[13][14][15][26][27][28]35,[46][47][48][49] Based on the available experimental observations, there are many morphological pictures for PEDOT:PSS proposed in various studies. 23,25,27,40,48,[50][51][52][53][54][55][56][57][58][59][60][61] Some representative pictures are summarized in Fig. 1.…”

Synthesis of Ultrathin PEDOT on Carbon Nanotubes and Shear Thinning Xanthan Gum‐H2SO4 Gel Electrolyte for Supercapacitors

“…For obtaining maximum performance from PEDOT, it is necessary to lower the amount of unused PEDOT or in other words, it is desirable to confine the PEDOT film thickness well within few nanometers. However, thin films generally show high sheet resistance which adversely affects the performance . Thus, a viable strategy would be to form a very thin layer of PEDOT on a conducting core.…”