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Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is the most successful transparent conductive polymer widely used in functional organic devices. However, its potential in fabrication of highly conductive electrodes still has not been fully explored. This paper is an attempt to fill the existing gap of knowledge on possible post-treatments of dimethyl sulfoxide (DMSO)-doped PEDOT:PSS thin films. In the present study, surface morphology, optical and electrical properties of untreated and sulfuric acid treated DMSO-doped PEDOT:PSS multilayers on the glass coverslip substrates are examined. It is demonstrated that short-time sulfuric acid treatment enhances electrical and optical properties, and smoothens surface of the transparent conductive films. Enhancement of electrical conductivity by more than 30 % can be associated with increase in doping level, removal of excess PSS and accompanied shape alterations of the conjugated PEDOT chains. Acid treatment also results in smoother transmittance spectra and a slight improvement of optical transparency. Hence, sulfuric acid post-treatment can be considered as a simple and inexpensive technique for the complementary doping of DMSO-doped PEDOT:PSS films with the aim to develop the more effective transparent electrodes.

MoO2 films were prepared by electrodeposition under potential controlled conditions from an aqueous alkaline solution of sodium molybdate. Optical microscopy showed that films of different morphology were deposited. The surface roughness and grain size were determined by atomic force microscopy. The characterization of as-deposited films by X-ray diffraction analysis revealed their amorphous nature. The optical constants of films were derived from transmittance spectra recorded in the 310–1100 nm wavelength range. All films were highly absorptive and showed a direct band to band transition. From the absorption edge data, the values of the optical band gap E g and the Urbach energy E U were determined based on Tauc’s model. The influence of film thickness on the extinction coefficient k, refractive index n, absorption coefficient a and the band gap energy E g was studied.

The surface plasmon resonance evaluation of colloidal metal nanoparticles, synthesized in organic medium, is reported in this work. Metal salts were dissolved in dioxane/AOT solution and reduced by hydrazine hydrate under vigorous stirring. Optical properties of obtained colloidal nanoparticles were investigated by UV VIS spectroscopy. Theoretical predictions of optical properties of metal nanoparticles were made by means of the Mie theory and the Drude free-electron model. Geometrical parameters and distribution of metal nanoparticles in colloidal solutions were characterized by atomic force microscopy. The results show that Ag, Cu, and Co nanoparticles, synthesized in organic medium distinguish plasmonic properties. Surface plasmon resonance bands were obtained in all cases: Ag at 430 nm, Cu at 570 nm, Co at 350 nm (SPR1) and 430 nm (SPR2). Comparing theoretical evaluation of nanoparticles size with atomic force microscopy analysis, we can assume that our calculations are accurate. It was found that dominating nanoparticles diameter in Ag colloidal solution is ≈ 150 nm, in Cu colloidal solution is ≈ 70 80 nm and in Co colloidal solution is ≈ 150 nm. It can be concluded that nanoparticles with enhanced plasmonic properties synthesized in organic medium can be widely used in order to increase e ciency of various optical elements.