TY - JOUR
T1 - Ultrathin Gold Nanowires with the Polytetrahedral Structure of Bulk Manganese
AU - Vargas, Jorge A.
AU - Petkov, Valeri
PY - 2018/9/10
Y1 - 2018/9/10
N2 - Despite the intensive interest in thin gold nanowires for a variety
of technologically important applications, key details of the mechanism of their
formation and atomic-scale structure remain unknown. Here we synthesize
highly uniform, very long, and ultrathin gold nanowires in a liquid-phase
environment and study their nucleation and growth using in situ high-energy
synchrotron X-ray diffraction. By controlling the type of solvents, reducing
agents, and gold precursor concentration, it is shown that the nucleation and
growth of gold nanowires involve the emergence and self-assembly of transient
linear gold complexes, respectively. In sharp contrast with the face-centeredcubic
bulk gold, the evolved nanowires are found to possess a tetrahedrally close
packed structure incorporating distorted icosahedra and larger size coordination polyhedra of the type observed with the
room-temperature phase of bulk manganese. We relate the complexes to synergistic effects between the selected precursor
and reducing agents that become appreciable over a narrow range of their molar ratios. We attribute the unusual
structural state of gold nanowires to geometrical frustration effects arising from the conflicting tendencies of assemblies of
metal atoms to evolve toward attaining high atomic packing density while keeping the atomic-level stresses low, ultimately
favoring the growth of cylindrical nanowires with a well-defined diameter and atomically smooth surface. Our work
provides a roadmap for comprehensive characterization and, hence, better understanding of 1D metallic nanostructures
with an unusual atomic arrangement and may have important implications for their synthesis and performance in practical
applications.
AB - Despite the intensive interest in thin gold nanowires for a variety
of technologically important applications, key details of the mechanism of their
formation and atomic-scale structure remain unknown. Here we synthesize
highly uniform, very long, and ultrathin gold nanowires in a liquid-phase
environment and study their nucleation and growth using in situ high-energy
synchrotron X-ray diffraction. By controlling the type of solvents, reducing
agents, and gold precursor concentration, it is shown that the nucleation and
growth of gold nanowires involve the emergence and self-assembly of transient
linear gold complexes, respectively. In sharp contrast with the face-centeredcubic
bulk gold, the evolved nanowires are found to possess a tetrahedrally close
packed structure incorporating distorted icosahedra and larger size coordination polyhedra of the type observed with the
room-temperature phase of bulk manganese. We relate the complexes to synergistic effects between the selected precursor
and reducing agents that become appreciable over a narrow range of their molar ratios. We attribute the unusual
structural state of gold nanowires to geometrical frustration effects arising from the conflicting tendencies of assemblies of
metal atoms to evolve toward attaining high atomic packing density while keeping the atomic-level stresses low, ultimately
favoring the growth of cylindrical nanowires with a well-defined diameter and atomically smooth surface. Our work
provides a roadmap for comprehensive characterization and, hence, better understanding of 1D metallic nanostructures
with an unusual atomic arrangement and may have important implications for their synthesis and performance in practical
applications.
M3 - Article
VL - 12
SP - 9521−9531
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
ER -