Preparation of highly loaded copper(II) oxide nanoparticle suspensions for LIFT-printing of electronics

Printing of electronics has rapidly gained ground on both laboratory and industrial level, showcasing the potential of additive microfabrication techniques and functional nanotechnology-based materials. Laser-induced forward transfer (LIFT) follows the trends of microelectronics towards miniaturized electronic components, by increasing the printing speed and accuracy. The study focuses on the preparation of highly loaded copper(II) oxide nanoparticle – based inks for LIFT applications. Suspensions of 25% w/w solids loading have been prepared in ethylene glycol – water, 1,3-propylene glycol – water and 1,2-propylene glycol – water co-solvent media and characterized via UV-Visible Spectroscopy, Transmission Electron Microscopy, rheological measurements, Thermogravimetric Analysis and Differential Scanning Calorimetry. The samples showed good stability in the course of two months and the nanoparticles were spherical, with diameters of 14, 9 and 8 nm, forming small, flower-like clusters of 25, 21 and 23 nm, respectively. In addition to the above, their non-Newtonian, shear-thinning behavior and zero shear viscosities of 6.12·103, 1.60·102 and 5.25 Pa·s, as well as the smooth evaporation of their media during heating highlight their potential for LIFT applications.