Direct printing of silver nanoparticles by an agarose stamp on planar and patternedsubstrates

Abstract

In this study, we have used an agarose stamp to conduct direct printing of silver nanoparticles,nanowires and nanoplates on both planar and structured substrates. Nanoparticle solutioncould be first coated on an agarose stamp, and then transferred to a planar substrate.Micro-patterns comprising metal nanoparticles could be printed on planar substrates withoutthe formation of residual layers. Thus a three-dimensional metal microstructure could beeasily fabricated. The patterning of electrodes by printing Ag nanowires directly onTiO2 was also demonstrated to fabricate resistive random access memory (RRAM) devices byall-solution-processing methods. By using a flat agarose stamp, the patterns printed on themicrostructured substrates were quite different from those on the nanostructuredsubstrates. On the microstructured substrates, direct printing could print silvernanoparticles onto the protrusion surface, and could print silver layers as thickas several microns, useful for high conductivity electrodes. On the substrateswith nanostructures such as photonic crystals or nano-gratings, direct printingcould transfer nanoparticles into the grooves or cavities only due to the contactof the agarose stamp with the groove or concavity surface. A new approach tofabricate metal wire grid polarizers was further demonstrated. A nanoporousagarose stamp has a good potential for printing using nanoparticle suspension.