Optimizing the electrical properties of PEDOT:PSS films by co-solvents and their application in polymer photovoltaic cells

A simple optimizing approach that improves the electrical properties of poly (3,4-ethylenedioxylthiophene):poly(styrenesulfonate) (PEDOT:PSS) films and their application in heterojunction diodes and polymer photovoltaic cells is presented in this paper. The optimizing process is performed by mixing the organic solvents n-methyl-2-pyrrolidone and methanol along with dimethyl sulfoxide into PEDOT:PSS solution achieving the facile combination of the solvent effect. Electrical conductivity varies from 0.16 to 194 S/cm by variation in the concentration of n-methyl-2-pyrrolidone. It is shown that the enhancement in conductivity of PEDOT:PSS films with co-solvents by three orders of magnitude is achieved compared to pristine PEDOT:PSS with transparency >92% in the visible region. The heterojunction diodes fabricated with co-solvents studied in this work showed rectifying behavior, and polymer photovoltaic cells fabricated with the co-solvents exhibited photovoltaic performance.