Microwave annealing as fast alternative for hotplate annealing of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate

Abstract

Poly(3,4-ethylenedioxythiophene): poly(styrene-sulfonate) (PEDOT:PSS) is used in a variety of organic based electronic devices and requires a time consuming thermal annealing step after deposition, to remove solvents and increase the conductivity. In order to speed-up this process, microwave annealing is investigated as post-deposition treatment of PEDOT:PSS thin films. In order to assess the feasibility of this annealing technique a comparative study between microwave annealing and conventional hotplate annealing is performed. PEDOT:PSS films treated with both techniques were characterized and compared by their morphology and their sheet resistance. In order to confirm the assumption that microwave annealing is the faster technique, the annealing times for both techniques where measured. No difference in the thin film morphology was observed for microwave annealed compared to the hotplate annealed samples. The measurements of the sheet resistance show that at sufficient low power setting of the microwave, e.g.: 150W, the sheet resistance of the microwave annealed PEDOT:PSS films are comparable to those annealed using the hotplate technique while decreasing the annealing time by 6 times. These results show that microwave annealing is a feasible fast annealing technique for PEDOT:PSS thin films and can therefor reduce the total processing time of organic and PEDOT:PSS based electronic applications.