posted on 2022-12-29, 03:29authored byQi Li, Charles J. Zeman, Bora Kalkan, Kristin Kirschbaum, Christopher G. Gianopoulos, Abhinav Parakh, David Doan, Andrew C. Lee, John Kulikowski, George C. Schatz, Guoyin Shen, Martin Kunz, X. Wendy Gu
The ability to gradually modify the atomic structures
of nanomaterials
and directly identify such structural variation is important in nanoscience
research. Here, we present the first example of a high-pressure single-crystal
X-ray diffraction analysis of atomically precise metal nanoclusters.
The pressure-dependent, subangstrom structural evolution of an ultrasmall
gold nanoparticle, Au25S18, has been directly
identified. We found that a 0.1 Å decrease of the Au–Au
bond length could induce a blue-shift of 30 nm in the photoluminescence
spectra of gold nanoclusters. From theoretical calculations, the origins
of the blue-shift and enhanced photoluminescence under pressure are
investigated, which are ascribed to molecular orbital symmetry and
conformational locking, respectively. The combination of the high-pressure in situ X-ray results with both theoretical and experimental
optical spectra provides a direct and generalizable avenue to unveil
the underlying structure–property relations for nanoclusters
and nanoparticles which cannot be obtained through traditional physical
chemistry measurements.