Field emission study of change in work function of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) film

Modification of the work function of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) was obtained by irradiating PEDOT:PSS film in vacuum with 254 nm ultraviolet (UV) light. Work function change was measured by a field emission technique in situ. A small increase in the work function was observed after a brief period of irradiation. When the irradiation time was prolonged, a monotonous reduction in the work function occurred in high vacuum. The effect of oxygen on UV-illuminated PEDOT:PSS was studied, and recovery of the work function was achieved after 3 h of oxygen exposure. The result shows that tuning the work function of PEDOT:PSS in the desired direction with UV treatment is possible.