It was demonstrated that non-ionic surfactants reduce the solution's surface tension, improving the wettability of hydrophobic substrates. Even 0.05% of Neonol can significantly affect the surface tension of the aqueous PEDOT:PSS solution on fused silica substrates. However, higher percentages of Neonol increase the electrical resistivity of the polymer layer. For film deposition, a minimum neonol volume fraction of 0.005 vol.% was required. In this work examined how adding different volume fractions of dimethyl sulfoxide affected the electrical conductivity of PEDOT:PSS films. Two methods were used to add dimethyl sulfoxide to the films: the pre-adding method and the post-spin-rinsing method. The electrical properties of the films with and without the addition of dimethyl sulfoxide were measured. Films produced using the dimethyl sulfoxide post-spin-rinsing method exhibited the highest conductivity achieved in this paper, reaching 780 S/cm. The results of time degradation studies conducted during the research demonstrate that the electrical conductivity of the samples, on average, decreased by more than half after a two-week period.