Thin films of organic semiconductor PEDOT:PSS deposited onto silicon and fusedsilica substrates. These films were then treated with sulfuric acid(H2SO4) for various amounts of time (i.e., 10, 20, 40,60, and 80 minutes). Preliminary results obtained with FT-IR, UV-VIS, and VanDerPauw conductivity methods suggest that the H2SO4removes the PSS isonomer from the PEDOT:PSS system. This PSS removal alsoinduces a decrease in film thickness.