Graphene–Ag nanohexagonal platelets-based ink with high electrical properties at low sintering temperatures

Abstract

Printed-electronics inks belong to a class of novel functional conductive inks that can be used to form high-precision conducting lines or circuits on various flexible substrates. Previous studies have reported conductive inks produced by the reduction and membrane separation method for use in flexible devices. However, it remains a challenge to synthesize conductive inks with high electrical properties at low sintering temperatures, which restricts their range of applications. Herein, we prepare inkjet-printed patterns of conductive inks consisting of Ag nanohexagonal platelets (AgNHPs) as the main component and containing graphene (GE) in different contents. It is found that GE improves the electrical conductivity of the patterns when sintering is done at relatively low temperatures. For instance, when the GE content is 0.15 mg ml−1, the resistivity is the lowest. When sintering is done at 150 °C, the resistivity (2.7 × 10–6 Ω · cm) of the GE-AgNHPs conductive ink (GE: 0.15 mg ml−1) is 14% of that of the AgNHPs conductive ink; on the other hand, after sintering at 50 °C, this ratio is 2%. It is also found that, with the increase in GE content, the resistivity of the GE-AgNHPs conductive ink increases. This study on GE-AgNHPs conductive inks sintered at low temperatures should further the development of flexible touch screens.