Single-Step Assembly of Large-Area, Transparent Conductive Patterns Induced Through Edge Adsorption of Template-Confined Au-Thiocyanate

Fabrication of patterned metallic films through chemical means is a primary objective in the emerging field of "bottom-up" lithography. We present a simple technology for generating large area, highly uniform patterns of conductive gold microwires. The approach is based upon dissolution of a gold complex, Au(SCN)₄^-, in an organic-solvent/water mixture and confining the solution underneath polymeric molds. We show that Au(SCN)₄^- undergoes spontaneous crystallization/reduction, producing metallic Au microwires tracing the contours of the templates. Importantly, no shape-directing molecules or reducing agents are required for Au microwire formation, as the thiocyanate ligands both donate the reducing electrons as well as direct the crystallization process of the Au patterns. We demonstrate application of the new technology for creating highly transparent conductive films. A new "chemical Au patterning" technology is demonstrated. Spontaneous formation of large-area Au patterns comprising uniform Au microwires is achieved through placing polymer molds upon films comprising Au(SCN)₄^- dissolved in an organic solvent/water mixture. The gold thiocyanate undergoes spontaneous crystallization/reduction within the confined spaces underneath the molds, yielding microwire patterns which trace the mold applied.