Stable colloidal dispersions of silicon nanoparticles for the fabrication of films using inkjet printing technology

The formation of stable colloidal dispersions of nanoparticles is essential for the manufacture of electronic and optoelectronic devices using cost-effective printing technologies. In this study, we examined the stability of silicon nanoparticles (Si-NPs) in aqueous medium at different pH. The Si-NPs show high zeta potential values within pH = 6.5 - 8.5. In addition, the Si-NPs do not show any isoelectric point in the pH range studied. It is observed that the stability of Si-NPs in aqueous medium increases after the addition of ethanol. In order to stabilize Si-NPs in organic solvents, their surface is functionalized with alkyl groups via a thermally induced alkylation process. The functionalized Si-NPs form nice, transparent dispersions in a variety of organic solvents and no sedimentation of functionalized samples was observed over any period of time. Fabricating films of Si-NPs using inkjet printing is currently under investigation.