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In-Depth Information
Fig. 11.2
UV/Vis spectra of
gold nanoparticles heated for
a
40 s
b
70 s. (Adopted with
kind permission from Arshi
et al.
2011a
)
3.2 Silver Nanoparticles
We presented a simplest, cheapest and environmentally benign synthesis of silver
nanocrystals using sugar as the reducing-cum-stabilizing agent in ambient condi-
tions without any solvent. The structural analyses of the as-synthesized nanocrys-
tals were performed using X-ray diffraction (XRD). The morphological study of
the sample was done using Atomic force microscopy (AFM) and TEM. The optical
study of the synthesized product was performed using UV/Vis spectroscopy.
Figure
11.3
shows the XRD pattern of the as-synthesized silver nanocrystals.
The XRD pattern of silver nanocrystals showed a single phase nature with face-
centered cubic (FCC) structure. No secondary phase was detected and the high in-
tensity of peaks revealed the high crystalline nature of the as-synthesized silver
nanocrystals. The average grain size calculated by using Debye-Scherrer formula
(Cullity and Stock
2001
) was found to be ~19 nm.
The UV/Vis absorption spectrum of the silver nanocrystals is shown in Fig.
11.4
.
A strong absorption peak at approximately 426 nm of nanosized silver nanocrystals
was observed, which is the characteristic of the surface plasmon resonance of Ag
materials. Figure
11.5a
,
b
depict the topographical 2D and 3D AFM images of silver
nanocrystals. It is clear from Fig.
11.5a
,
b
that most of the grains are in the size rang-
ing from 10-20 nm with average diameter of ~18 nm.
This is evidently in accordance with the results obtained by XRD. Figure
11.6a
shows the TEM micrograph of homogeneous silver nanocrystals with particle size
in the range of about 10-30 nm. It is clear from the TEM micrograph that the par-
ticles are nearly cubic in shape. A statistical distribution of particle size is shown
in Fig.
11.6b
, which shows average particle size of a silver nanocrystal to be about
~22 nm.
