Intermetallic Nanocrystal Discovery through Modulation of Atom Stacking Hierarchy

A library of compositionally and structurally welldefined Au-Cu alloy nanocrystals has been prepared via scanning probe block copolymer lithography. These libraries not only allow one to map compositional and structure space but also the conditions (e.g., cooling rate) required to access specific structures. This approach enabled the realization of a previously unobserved architecture, an intermetallic nanoprism, that is a consequence of hierarchical atom stacking. These structures exhibit distinctive diffraction patterns characterized by non-integer-index, forbidden spots, which serve as a diagnostic indicator of such structures. Inspection of the library's pseudospherical particles reveals a high-strain cubic-tetragonal interfacial configuration in the outer regions of the intermetallic nanocrystals. Since it is costly and time-consuming to explore the nanomaterials phase space via conventional wet-chemistry, this parallel kinetic-control approach, which relies on substrate-and positionally isolated particles, may lead to the rapid discovery of complex nanocrystals that may prove useful in applications spanning catalysis and plasmonic sensing.

Automated summary

A library of well-defined Au-Cu alloy nanocrystals with specific compositions and structures has been created using scanning probe block copolymer lithography, providing a valuable tool for mapping composition and structure space and determining the necessary conditions for accessing specific structures. This approach has led to the discovery of a previously unseen architecture, called an intermetallic nanoprism, that is formed through hierarchical atom stacking. The distinctive diffraction patterns observed in these structures serve as diagnostic indicators. Examination of the library's pseudospherical particles revealed a specific interfacial configuration within the intermetallic nanocrystals. This parallel kinetic-control approach offers a rapid and cost-effective method for exploring complex nanocrystals that could have applications in catalysis and plasmonic sensing.