TY - JOUR
T1 - Au329-xAgx(SR)84 Nanomolecules
T2 - Plasmonic Alloy Faradaurate-329
AU - Kumara, Chanaka
AU - Zuo, Xiaobing
AU - Cullen, David A.
AU - Dass, Amala
N1 - Publisher Copyright:
© 2015 American Chemical Society.
PY - 2015/8/20
Y1 - 2015/8/20
N2 - Though significant progress has been made to improve the monodispersity of larger (>10 nm) alloy metal nanoparticles, there still exists a significant variation in nanoparticle composition, ranging from ±1000s of atoms. Here, for the first time, we report the synthesis of atomically precise (±0 metal atom variation) Au329-xAgx(SCH2CH2Ph)84 alloy nanomolecules. The composition was determined using high resolution electrospray ionization mass spectrometry. In contrast to larger (>10 nm) Au-Ag nanoparticles, the surface plasmon resonance (SPR) peak does not show a major shift, but a minor ∼10 nm red-shift, upon increasing silver content. The intensity of the SPR peak also varies in an intriguing manner, where a dampening is observed with medium silver incorporation, and a significant sharpening is observed upon higher Ag content. The report outlines (a) an unprecedented advance in nanoparticle mass spectrometry of high mass at atomic precision; and (b) the unexpected optical behavior of Au-Ag alloys in the region where nascent SPR emerges; specifically, in this work, the SPR-like peak does not show a major ∼100 nm blue-shift with Ag alloying of Au329 nanomolecules, as shown to be common in larger nanoparticles.
AB - Though significant progress has been made to improve the monodispersity of larger (>10 nm) alloy metal nanoparticles, there still exists a significant variation in nanoparticle composition, ranging from ±1000s of atoms. Here, for the first time, we report the synthesis of atomically precise (±0 metal atom variation) Au329-xAgx(SCH2CH2Ph)84 alloy nanomolecules. The composition was determined using high resolution electrospray ionization mass spectrometry. In contrast to larger (>10 nm) Au-Ag nanoparticles, the surface plasmon resonance (SPR) peak does not show a major shift, but a minor ∼10 nm red-shift, upon increasing silver content. The intensity of the SPR peak also varies in an intriguing manner, where a dampening is observed with medium silver incorporation, and a significant sharpening is observed upon higher Ag content. The report outlines (a) an unprecedented advance in nanoparticle mass spectrometry of high mass at atomic precision; and (b) the unexpected optical behavior of Au-Ag alloys in the region where nascent SPR emerges; specifically, in this work, the SPR-like peak does not show a major ∼100 nm blue-shift with Ag alloying of Au329 nanomolecules, as shown to be common in larger nanoparticles.
KW - alloy metal nanoparticles
KW - electrospray ionization mass spectrometry
KW - surface plasmon resonance
UR - http://www.scopus.com/inward/record.url?scp=84939865159&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.5b01395
DO - 10.1021/acs.jpclett.5b01395
M3 - Article
AN - SCOPUS:84939865159
SN - 1948-7185
VL - 6
SP - 3320
EP - 3326
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 16
ER -