ITO-free OLEDs utilizing inkjet-printed and low temperature plasma-sintered Ag electrodes

Abstract

We report an inkjet-printed indium tin oxide (ITO)-free electrode made from a particle-free silver ink. After printing, an argon plasma is used to reduce the silver ions in the ink to metallic silver. This process does not require high temperatures and is therefore suitable for use with temperature sensitive substrates. Printed silver layers show good optical transmittance and electrical conductivity. To demonstrate the capabilities of the electrodes, inverted ITO-free organic light-emitting diodes (OLEDs) were produced via solution processing. In terms of luminance and efficacy, the devices containing the printed electrodes show improved luminance and current efficacy compared to ITO-based reference devices. When fabricated with flexible substrates, the printed OLEDs show high bending stability, enabling flexible applications.