Work Function Controlled Zn:Cu Electrode for All-Printed Polymer Diode

Abstract

We have developed a pressure annealing technique for fabricating low-work-function metal patterns on plastic substrates. The pressure annealing technique can destroy the metal oxide layer and can form a conductive layer on printed metal patterns. Furthermore, we have confirmed that a binary solid solution is easily formed on metal patterns including two kinds of metal particles by using the pressure annealing technique. Changing the composition ratio of the binary metal paste led to the work function control of the pressure-annealed metal patterns. The formation of the binary solid solution was confirmed by X-ray diffraction (XRD) analysis, and work function was measured by photoelectron emission spectroscopy. In the case of the binary metal paste of Cu and Zn, we have succeeded in controlling work function from 3.8 to 5.0 eV. Since the Cu–Zn paste is composed of relatively cheap metals, this would be applicable to large-scale flexible electronic devices.