US Patent 7829139 Method of making nanoparticle wires

A new method of making self-assembled nanoparticle wires involves:(1) at about ambient temperature and at or near atmospheric pressure, immersing a hydrophilic solid substrate at a non-horizontal angle (e.g., vertically) into a suspension of nanoparticles in a solvent, the suspension having a negative meniscus, the immersion forming a solid-liquid-air interface at the meniscus of the suspension;(2) gradually exposing the immersed substrate to air by gradually removing (preferably evaporating) the suspension, thereby causing deposition of the nanoparticles at a first location on the substrate at the meniscus, thereby forming a first nanoparticle wire on the substrate;(3) after a first deposition time period, rapidly removing a portion of the suspension, thereby causing deposition to stop and then re-start at a second location on the substrate at the meniscus;(4) continuing to gradually expose the immersed substrate to air by gradually removing the suspension for a second deposition period, thereby forming a second nanoparticle wire on the substrate; and optionally(5) repeating steps (3) and (4) one or more times to form one or more successive nanoparticle wires on the substrate.The above method can also be used to form integrated nanoparticle wire arrays.