Metal Electrode Work Function Modification Using Aerosol Jet Printing

An aerosol jet printer is used to precisely control the deposition in 25 nm increments of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on an oxygen plasma-treated Ni (O2-Ni) electrode to modify its work function. As revealed by Kelvin probe measurements, the effective work function of the O2-Ni electrode is dependent on the thickness of the PEDOT:PSS coating. By precisely controlling the coating thickness, the effective work function of metal electrodes in polymer-based photodetectors can be tailored for improved device performance. This is verified by demonstrating a threefold increase in the photoresponse of a polymer-based Schottky barrier infrared photodetector.