98
S. E. H. Murph and A. Goriounova
Fig. 1 Scanning electron microscopy image of 21 nm in diameter gold nanoparticles prepared in
solution
Fig. 2 a Ultraviolet–visible spectra for gold nanoparticles solutions prepared in the absence of
stainless-steel wool (blue) and in the presence of stainless-steel wool filters (green); gold nanoparticles plasmon band’s position depends on the nanoparticle’s diameter; the distinctive absorbance
peak is redshifted (larger wavelength) for larger gold nanoparticles; and b noticeable color difference between the gold nanoparticles on stainless-steel wool solution (left, purple, 25 nm) and gold
nanoparticles free in solution (right, red, 21 nm). (Color figure online)
The optical properties of gold nanoparticles solutions resulted when produced
in the presence of stainless-steel wool differ slightly than those in solution. The
ultraviolet–visible spectra of these gold nanoparticles solution show a plasmon band
peak at 533 nm. The gold nanoparticle solution’s color was a purple-reddish color
(Fig. 2b). These results are in agreement with previous studies showing tunability
in plasmon band based on nanoparticle’s size [4, 9, 15, 17]. The plasmon band peak