Traversing the Periodic Table through Phase‐Separating Nanoreactors

Phase-separating nanoreactors, generated through either Dip Pen Nanolithography (DPN) or Polymer Pen Lithography (PPL) and capable of single nanoparticle formation, are compatible with almost every relevant element from the periodic table. This advance overcomes one of the most daunting limitations in high throughput materials discovery, specifically enabling the synthesis of broad swaths of the materials genome. Indeed, the platform is compatible with at least 52 metal elements of interest and almost an infinite number of combinations. In particular, it is discovered that surface-confined, attoliter-volume reactors made of polystyrene (PS) mixtures can be preloaded with metal salts spanning all but the alkali metals and subsequently transformed into single- or multi-component nanoparticles of well-defined dimensions. This is done in a three-step process, which initially involves the facilitation of precursor precipitation and localization with toluene vapor, followed by plasma treatment to remove the polymer reactor component, and then heating from 400-900 °C, depending upon precursor and desired end-state (degree of reduction and crystallinity). These phase-separating nanoreactors are used to produce metal and metal oxide nanoparticles, depending upon conditions, in a substrate-general manner.