Direct Electrostatic Toner Marking with Novel Electric Field Induced Hole Injection Between PEDOT:PSS and Molecularly Doped Polymer Layers of Arylamine

摘要

PEDOT.PSS is the one of the most promising and widely used material for low cost large area flexible displays owing to their easy solution processing and nanoscale patternability. In this work, hole injection between PEDOT.PSS thin film and molecularly doped polymer layers of arylamine has been studied in a bilayer device configuration. The electrical properties of the bilayer device have been examined by studying the charge-discharge, I-V and Time of Flight (TOF) characteristics of the devices. The work function of the PEDOT.PSS and aryl amine has been estimated by electrochemical measurements. Results show that PEDOT.PSS are efficient hole injectors to arylamine owing to their favorable molecular energetics. The efficiency of hole injection also depends on the conductivity of PEDOT and the strength of the electric field. The interfacial contact behavior between PEDOT and arylamine studied by steady state IV measurements and TOF measurements suggests that for highly conductive PEDOT:PSS, the hole injection is limited by the hole mobility in the charge transport layer where as for higher resistive PEDOT.PSS, it is injection limited. Based on these results, a discharge mechanism has been proposed for the bilayer device. Initial printing experiments were done on a xerographic development housing, where toner development on the bilayer device was observed at the exit of the development nip. Results suggested that the negatively biased magnetic brush plays a dual role in the print process. It first discharges the bilayer device with its negative bias followed by toner development to the discharged area. The use of this novel electric field induced hole injection process for direct toner marking is discussed.