Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS, is a polymeric composite that can substitute indium tin oxide (ITO), enabling ITO-free organic devices. However, PEDOT:PSS films have conductivities two orders of magnitude lower than ITO due to the presence of PSS, an insulator polymer added to provide water dispersion to PEDOT. To enhance the electrical performance of the films and overcome the insulator limitations, we prepared thin films of graphene oxide (GO) and PEDOT:PSS composites. The dried films were then treated with ethylene glycol (EG). An increment of two orders of magnitude in conductivity values was observed, as well as an increase in transmittance at the visible region. Also, GO:PEDOT:PSS thin films became more hydrophobic due to the partial removal of PSS. The mass ratio that is equal to 0.058 of GO/PEDOT provides higher electrical conductivity due to higher chain orientation of PEDOT as seen in the near edge X-ray absorption fine structure and resonant Auger spectroscopy measurements. The electrical transport follows the Mott Variable Range Hopping model for low temperature, showing that the conduction occurs in three dimensions. The solvent treatment increases the characteristic conductivity and decreases the activation hopping energy, with the characteristic temperature remaining almost unchanged. It indicates that the EG treatment promotes a decrease in charge transfer time and resistivity.

Due to issues related to the use of indium, the conjugated polymer poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate) (PEDOT:PSS) is considered as one of the main substitutes for indium tin oxide (ITO) in the structure of organic photovoltaics. Recent works demonstrated that the blend of PEDOT:PSS and graphene oxide (GO) can provide transparent and flexible electrodes with a higher efficiency than PEDOT:PSS itself. In this study, two series of cooled and not-cooled thin films of GO:PEDOT:PSS with different compositions of PEDOT:PSS (1, 5, 10, and 100% (v/v)) were investigated by spectroscopic and morphological techniques to evaluate the effect of the cooling treatment on their electronic and chemical structures, morphology, and carrier mobility. Surface- and bulk-sensitive near-edge X-ray absorption fine structure (NEXAFS) results probed at the sulfur K-edge showed that the cooled GO:PEDOT:PSS 5% blend is the most organized film, which also presented a faster electron delocalization time as probed by resonant Auger spectroscopy using the core-hole clock method. GO:PEDOT:PSS 5% offers the best synergetic effect among the blends, a result which is completely in agreement with electrical results.

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In the past few decades, technological advances have aroused the interest of industries and consumers for exible electronic devices. However, the substrates currently used, such as glass and polyethylene terephthalate (PET), present problems regarding their performance and destination, since the rst is di cult to handle and the second comes from non-renewable sources. Common properties required in substrates to provide their use in organic electronics are exibility, stability and su cient transparency. Therefore, as a sustainable and e cient alternative, the present study aimed to develop a totally cellulose-based substrate, a natural abundant polymer that presents thermal stability, mechanical strength, recyclability and is biodegradable. It was produced different substrates using micro brils from Eucalyptus sp. A pure micro ber substrate weighing 25 g m -² was obtained by the vacuum ltration method and paper-forming machine. The other four substrates were obtained by the casting method containing cellulose acetate matrix and freeze-dried micro brils reinforcement at different concentrations. In addition, a substrate containing 1.0 % of the suspended micro brils as reinforcement in the cellulose acetate matrix was produced. A conductive thin lm of Poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT:PSS) was deposited by air-brush technique as an electrode to evaluate the electrical performance of the substrates. The obtained lms were characterized by their optical, thermal and morphological properties, showing a great potential to be used as substrate in organic electronic devices.

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In the past few decades, technological advances have aroused the interest of industries and consumers for flexible electronic devices. However, the substrates currently used, such as glass and polyethylene terephthalate (PET), present problems regarding their performance and destination, since the first is difficult to handle and the second comes from non-renewable sources. Common properties required in substrates to provide their use in organic electronics are flexibility, stability and sufficient transparency. Therefore, as a sustainable and efficient alternative, the present study aimed to develop a totally cellulose-based substrate, a natural abundant polymer that presents thermal stability, mechanical strength, recyclability and is biodegradable. It was produced different substrates using microfibrils from Eucalyptus sp. A pure microfiber substrate weighing 25 g m-² was obtained by the vacuum filtration method and paper-forming machine. The other four substrates were obtained by the casting method containing cellulose acetate matrix and freeze-dried microfibrils reinforcement at different concentrations. In addition, a substrate containing 1.0 % of the suspended microfibrils as reinforcement in the cellulose acetate matrix was produced. A conductive thin film of Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was deposited by air-brush technique as an electrode to evaluate the electrical performance of the substrates. The obtained films were characterized by their optical, thermal and morphological properties, showing a great potential to be used as substrate in organic electronic devices.