Laser Annealing-Induced Generation and Phase Transformation of High Entropy Metal Alloy and Ceramic Nanostructures

Metal-based inorganic nanomaterials made up of dissimilar elements have large functional potentials in various fields and applications such as catalysis, sensors and bioengineering. The control of crystal phase and composition of multicomponent nanoparticles is a powerful and effective strategy to introduce new unique physicochemical properties, functionalities and applications. Here we describe a millisecond laser annealing approach that provides control of crystal phases, compositions and functional properties of five-elemental multicomponent nanoparticles of metal alloys, oxides, and nitrides. Laser irradiation of an identical five-metal salt precursor mixture for different laser heating times (from 0.25 to 250 milliseconds) allows control of supercooling kinetics and reaction pathways toward multicomponent alloy nanoparticles have single and multiphasic solid solution characteristics, compositions and new physiochemical properties. In addition, laser annealing of a five-component nitride-former precursor mixture at different laser power levels provides selectivity in the formation of multicomponent tetragonal rutile oxide nanoparticles and phase transformation into cubic rock salt nitride nanoparticles. The method is highly generalizable and further provides access to multidimensional mesoporous metal nitride nanostructures. The resultant high entropy alloy nanoparticles enable various applications, including growth of high-quality carbon nanotubes, stable and efficient hydrogen evolution reaction as well as antimicrobial properties against E. Coli species.