Investigation of the effect of organic solvents on the electrical characteristics of PEDOT:PSS/p-Si heterojunction diodes

Poly (3,4- ethylenedioxythiophene) - poly (styrenesulfonic acid) (PEDOT:PSS) is a widely used polymer in organic electronics. In the present study, spin coated PEDOT:PSS films on Si substrates and doped with different organic solvents were analyzed. The influence of different solvents such as n-methyl-2-pyrrolidone, dimethyl formamide, dimethyl sulfoxide, ethylene glycol, and methanol on the morphology, transmittance and work function of PEDOT:PSS films as well as on the electrical properties of Au/PEDOT:PSS/p-Si/In-Ga heterojunction diodes is presented. It is shown that PEDOT:PSS films doped by various organic solvents exhibited improved conductivity (by two orders of magnitude) and transparency (> 85%) in the visible region. Various organic solvents modified heterojunction diodes studied in this work showed rectifying behavior with ideality factors in the range of 1.9-3.2.