Biology Reference
In-Depth Information
Figure 13.12
TEM
images
of
(a)
a
superparticle
made
of
Fe
O
3
4
nanocrystals with a diameter of 8.9
±
0.4 nm, showing the
{200}
superlattice-fringes with a spacing of 8.3 nm; (b) a
superparticle made of CdSe nanocrystals with a diameter
of 6.3
SL
±
0.3 nm; the image is viewed along the [111] axis
of the superlattice, showing {022}
superlattice-fringes
with a spacing of 4.3 nm; (c) a superparticle made of gold
nanocrystals with a diameter of 5.4
SL
±
0.3 nm, viewed along
the [011] zone axis, showing {111}
fringes with a spacing
of 6.2 nm. (d) The Raman spectrum of rhodamine-6G doped
supercrystalline
SL
colloidal
superparticles
made
of
gold
nanocrystals with a diameter of 5.4
±
0.3 nm. Scale bars: 20
nm. From Ref. [20] with permission.
13.4.3
Nonspherical Supercrystalline Superparticles
As in nanocrystal synthesis, the shape control in superparticle
synthesis is much more difficult than the size control.
Because
the internal energy of colloidal superparticles is normally slightly
higher than the thermal energy, the formation of their shapes is
under thermodynamic control, in which the tendency of minimizing
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