Res. Chem. Intermed.
, Vol. 31, No. 7–8, pp. 595–603 (2005)
Also available online - www.vsppub.com
Complexation of gold and silver nanoparticles
with radiolytically-generated radicals
, H. S. MAHAL
, S. KAPOOR
and T. MUKHERJEE
Synchrotron Radiation Section, Bhabha Atomic Research Centre, Mumbai 400 085, India
Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre,
Mumbai 400 085, India
Received 20 April 2004; accepted 4 June 2004
Abstract—The reactivity of (SCN)
and phenoxyl radicals in aqueous solution, generated by
pulse radiolysis, was studied on gold and silver nanoparticle surfaces. The spectral changes associated
with chemical interaction of radicals with metal nanoparticles were elucidated using time-resolved
absorption spectroscopy. The resultant complexes of (SCN)
with Au nanoparticles have
shown a strong absorption band at 390 nm and 260 nm, respectively. The stability of the particles after
adsorption of SCN
and phenols was measured by steady-state absorption. It has been shown
that the concentration of CTAB plays a signiﬁcant role in the stabilization of particles in the presence
of an adsorbate.
Keywords: Pulse radiolysis; electron transfer; nanoparticles.
In recent years, the emerging ﬁeld of metal nanoparticles has attracted much interest
because of their size- and shape-dependent electronic properties [1–10]. Coinage
metals, such as Ag, Cu and Au, have a surface plasmon absorption band in the
visible region. This facilitates the study of the changes occurring on the absorption
of organic molecules or on modiﬁcation of their surface [11 –16].
It is known that a noble metal, for example, Pt, promotes interfacial charge-
transfer processes by acting as a sink for photo-induced charge carriers [17, 18].
Metal nanoclusters of Au and Ag show unusual properties on chemically binding
with functional groups such as
SH, CNS, citrate, etc. Such properties of
metals have been exploited to make superstructure assemblies. Recently, it has
been exploited for important applications, such as designing nanoscale materials
for biological nanosensors and optoelectronic nanodevices [19–21].
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