Surface modification of PEDOT: PSS film by chemical vapor texturing process for enhanced organic photovoltaics

Abstract

Surface modification of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) film was performed using chemical vapor texturing process of HNO3 vapor. Textured PEDOT:PSS film exhibits higher root-mean-square roughness of 14.43 nm than pristine PEDOT:PSS film of 11.87 nm with small decrease in thickness. Moreover, approximate one-half reduction of sheet resistance is measured. In correspondence with roughness, increasing optical transmittance in the visible region and reducing water contact angle are explored. The reduction of water contact angle implies that active layer can be deposited on the textured film with better coverage to improve interfacial contact for OPV fabricating process. This improvement facilitates charge transfer in OPV device which causes the increase of short-circuit current density (Jsc) from 7.42 mA/cm2 to 8.01 mA/cm2. The increased Jsc is the major photovoltaic parameter in OPV enhancement. Therefore, the PEDOT:PSS film textured with the chemical vapor texturing process is demonstrated as an efficient rough film for OPV enhancement. Furthermore, the rough film modified using the process could be suggested for applying in several thin-film based devices.