Insight into the Mechanism of Single-Metal-Atom Tailoring on the Surface of Au–Cu Alloy Nanoclusters

Tailoring the surface structure of
nanomaterials is desirable for
investigating their mechanisms and properties from a nanochemistry
perspective. The modification of the surface of metal nanoparticles
with a single metal atom has proven difficult, which has hindered
the understanding of the contribution of different motifs in nanoclusters
to their properties. Herein, we report single-metal-atom surface tailoring
by thermally etching the nanocluster AuxCu15–x(DPPMH)3(SPhCl2)9 (x = 8 or 9) to obtain AuxCu16–x(DPPMH)2(DPPM)­(SPhCl2)9 (x = 9 or 10) nanoclusters. An Au7Cu4 core was observed in both nanoclusters, which can be regarded as
part of an icosahedron. Experiments and theoretical simulations revealed
the tailoring processes of the icosahedron. Both nanoclusters displayed
an NIR-II emission, and the introduction of the surface metal atom
led to a red-shift in the emission band from 983 to 1025 nm. This
work contributes to the development of precisely tailored nanocluster
structures and provides an understanding of structure–property
correlations.