Speeding up the glacial pace of new materials discovery is challenging, largely due to the seemingly endless array of substances with diverse properties that must be screened for specific applications. The problem is most pronounced at the nanoscale where a high-throughput combinatorial approach is required to understand Laser-induced heating of nanoparticles on micropillars for carbon nanotube growth. Source: Northwestern Universitystructure-function relationships.

A megalibrary tool developed with the aid of polymer pen lithography offers the potential to rapidly test millions of nanoparticles and optimize material selection or synthesis for a given end-use. The library substrate contains nanoparticles spatially encoded in terms of composition and size. The lithographic technique is used with an ink spray-coating method to form pen arrays, in which each pen has a different quantity and composition of ink.

The pen arrays deposit polymer dots loaded with different metal salts of interest onto a surface. Laser-induced heating transforms the deposited materials to nanoparticle at fixed composition and size. The method was used to synthesize gradients of gold-copper bimetallic nanoparticles that were then screened by in situ Raman spectroscopy to identify a new catalyst for single-walled carbon nanotube fabrication. The optimum composition for this application was identified in less than one week, a markedly shorter interval relative to conventional screening methods.

The technique resulting from a collaboration between Northwestern University and the U.S. Air Force Research Laboratory provides a platform for identifying structures with desired properties at a rate not previously possible.