TY  - EJOU
AU  - Zhang, Tong 
AU  - Yin, Binglun 
AU  - Wang, Pan 
AU  - Gao, Yang 

TI  - Quasi-Two-Dimensional Gold Nanosheets	with	Ultrahigh	Strength
T2  - The International Conference on Computational \& Experimental Engineering and Sciences

PY  - 2023
VL  - 25
IS  - 3
SN  - 1933-2815

AB  - Solid	gold	 usually	 holds	 face-centered-cubic	 structure	and	 relatively	low strength of	 102 MPa.	When	 the	
dimension	is	reduced to	the	nanoscale,	the	strength	of	metal	should	increase	accordingly,	due	to	size effect
or complex	 nanostructures [1-3]. However,	 reported maximum	 strength	 in	 gold	 nanostructures is	 yet	
considerably	lower	than	the	ideal strength (~6	GPa), referring	to the	stress	at	elastic instability	in	a	defectfree	crystal with	infinite	dimensions [3-5].	Herein,	the ideal	strength	of	gold	is	experimentally	achieved	in	a	
quasi-two-dimensional	 defect-free	 single	 crystalline nanosheet with	 hexagonal-close-packed	 (HCP)	
structure. Ultrathin	gold	nanosheets	with	a	high	aspect	ratio	(lateral	size	>101 μm, thickness <10 nm) were
synthesized	using	a	wet-chemical	method [6]. The	HCP	structure	of	the	ultrathin	nanosheets	was	confirmed	
by	high	resolution	transmission	electron	microscopy. Nanoindentation	measurements	were	performed	on	
suspended	gold	 nanosheets with	 various	 thicknesses using	an	atomic	 force	microscope.	The	mechanical	
behavior exhibits strong	thickness	dependence,	reaching a remarkable maximum strength	of	6.0	GPa, when	
the	thickness	is	less	than 10	nm.	First-principle	calculations	based	on	density	functional	theory	were	carried	
out	to	support	the	experiments. We	attribute	the	ultrahigh	strength	to	the	unique	defect-free	HCP	structure	
and	strong	surface effect.
KW  - Ultrathin	gold nanosheets; defect	free;	hexagonal-close-packing; ideal strength

DO  - 10.32604/icces.2023.010131