Precursors for forming a plurality of multielement materials of different compositions can be deposited on different portions of a common substrate according to a combinatorial approach. The substrate can be subjected to a thermal shock, thereby converting the deposited precursors into separate multielement materials on the substrate. The thermal shock can be a temperature greater than or equal to 500° C. and a duration less than 60 seconds. In some embodiments, each multielement material can be tested with respect to an electrical property, a chemical property, or an optical property. Based on the results of the testing, a composition of a multielement material can be determined for use in a predetermined application, such as use as a catalyst, a plasmonic nanoparticle, an energy storage device, an optoelectronic device, a solid-state electrolyte, or an ion conductive membrane.

Methods to fabricate tightly packed arrays of nanoparticles are disclosed, without relying on organic ligands or a substrate. In some variations, a method of assembling particles into an array comprises dispersing particles in a liquid solution; introducing a triggerable pH-control substance capable of generating an acid or a base; and triggering the pH-control substance to generate an acid or a base within the liquid solution, thereby titrating the pH. During pH titration, the particle-surface charge magnitude is reduced, causing the particles to assemble into a particle array. Other variations provide a device for assembling particles into particle arrays, comprising a droplet-generating microfluidic region; a first-fluid inlet port; a second-fluid inlet port; a reaction microfluidic region, disposed in fluid communication with the droplet-generating microfluidic region; and a trigger source configured to trigger generation of an acid or a base from at least one pH-control substance contained within the reaction microfluidic region.

Methods to fabricate tightly packed arrays of nanoparticles are disclosed, without relying on organic ligands or a substrate. In some variations, a method of assembling particles into an array comprises dispersing particles in a liquid solution; introducing a triggerable pH-control substance capable of generating an acid or a base; and triggering the pH-control substance to generate an acid or a base within the liquid solution, thereby titrating the pH. During pH titration, the particle-surface charge magnitude is reduced, causing the particles to assemble into a particle array. Other variations provide a device for assembling particles into particle arrays, comprising a droplet-generating microfluidic region; a first-fluid inlet port; a second-fluid inlet port; a reaction microfluidic region, disposed in fluid communication with the droplet-generating microfluidic region; and a trigger source configured to trigger generation of an acid or a base from at least one pH-control substance contained within the reaction microfluidic region.

Methods to fabricate tightly packed arrays of nanoparticles are disclosed, without relying on organic ligands or a substrate. In some variations, a method of assembling particles into an array comprises dispersing particles in a liquid solution; introducing a triggerable pH-control substance capable of generating an acid or a base; and triggering the pH-control substance to generate an acid or a base within the liquid solution, thereby titrating the pH. During pH titration, the particle-surface charge magnitude is reduced, causing the particles to assemble into a particle array. Other variations provide a device for assembling particles into particle arrays, comprising a droplet-generating microfluidic region; a first-fluid inlet port; a second-fluid inlet port; a reaction microfluidic region, disposed in fluid communication with the droplet-generating microfluidic region; and a trigger source configured to trigger generation of an acid or a base from at least one pH-control substance contained within the reaction microfluidic region.

This invention provides methods and systems to prepare replicate arrays from master arrays of liquid solutions. Replicate arrays of liquid solutions can be reacted to form product solid inorganic material arrays for analysis and selection of optimum processes and products with desirable properties.