DNA-Programmable AgAuS-Primed Conductive Nanowelding Wires-Up Wet Colloids

Self-assembly of nanomaterials, directed by molecular or supramolecular interactions, is a powerful strategy to build nanoscale devices. Despite many advantages of such solution-based processes, a big challenge is to realize interparticle ohmic contacts toward facilitated charge transport over a long distance. We report a new concept of primed nanowelding to thread solution-borne nanoparticles in prescribed assemblies. The process starts with a gap-specific deposition of Ag₂ E (E=S, Se) materials in pre-assembled gold structures, which spontaneously transform into AgAuE semiconductors via directional gold diffusion. Treatment with tributylphosphine generates alloyed Au/Ag welding spots that conductively wire-up nanoparticles into discrete "molecules" and micron-long "polymers". This method is compatible with DNA programming and delivers a possible way to solve the problem of the carrier-transport dilemma in solution-processed nanostructures for better-functioning nanodevices.