The optimization of conductive inks for 3D inkjet printing

Abstract

Commercially available nanoparticle precursor conductive inks are designed to prevent the blockage of the print-head nozzles by using low evaporation rate binder solvents. This low evaporation rate has the consequence of long drying times for those conductive inks which makes 3D printing of conductive routes a lengthy process. In this paper we identify a number of solvents that have suitable properties to prevent nozzle blockage and allow for enhanced drying rates so that multiple conductive layers can be printed within a short time to form 3D conductive elements. To achieve this propylene glycol monomethyl ether acetate (PGMEA) was used as a solvent to form a 30 wt% silver conductive ink which, after sintering, reached a resistivity of 1.66μΩ.m.