Chemistry Reference
In-Depth Information
(a)
(b)
(c)
Figure 2.13
TEM and HRTEM (inset) images of: (a) α-NaEuF
hexagonal
4
nanocrystals, (b) β-NaYF
nanorods, and (c) β-NaYF
4
4
nanoplates [75].
The above examples are by no means exhaustive but
representative among the vast amount of literatures on rare earth
1D nanostructures.
2.3.3
Two-Dimensional (2D) Rare Earth Nanostructures
In a kinetically driven growth regime, the growth of 1D nanorod is
typically promoted at a faster rate along a specific direction (e.g.,
z
-axis; Fig. 2.14a). On the other hand, when growth along an axis
is inhibited and preferential growth occurs along the other two
axes (e.g.,
-axes; Fig. 2.14b), the formation of disc-shaped
nanocrystals is facilitated. Unlike 1D rods, the formation of 2D
disc-shaped nanocrystals is not very common in colloidal systems.
Puntes
x
- and
y
. [76] is one of the first groups to report a strategy for the
synthesis of 2D nanostructures of metallic cobalt nanodiscs.
et al
Figure 2.14
1D rod versus 2D disc growth. (a) Preferential growth along
one direction (e.g.,
-axis) of a seed results in rod-shaped
nanocrystals; (b) growth along two directions (
z
-planes)
leads to the formation of disc-shaped nanocrystals [76].
x
- and
y
