Geoscience Reference
In-Depth Information
Figure 10.43 TEM and SEM images of CdS products obtained at 180
C for 5 h in mixed
solvents with different volume ratios: (a) of en, TEM image with SEM image as inset; (b)
15%, TEM image with SEM image as inset; (c) 65%, TEM image; (d) 100%, SEM image
with the upper right inset showing a magnified picture of the hexagonal ends of the long
rods, and the lower left inset showing the HRTEM image of a nanorod. The scale bars in the
TEM and SEM images all represent 100 nm. The scale bar in the HRTEM image is 5 nm.
Source: Photographs courtesy of Prof. Yan Li.
Yao et al.
[192]
have obtained nanowires of CdS using ethylenediamine as the
reaction medium. The experimental temperature was 140
C. The shape-controlled
synthesis of CdS nanocrystals in mixed solvents has been carried out by some
researchers
[193]
. They could obtain CdS nanotetrahedron, pencil-shaped nanorods,
tetrapod, prickly spheres, high aspect ratio hexagonal nanoprisms (
Figure 10.43
)
through adjusting the ratio of two solvents, namely ethylene diamine and ethylene
glycol under SCF conditions, and the experimental time and temperature. They did
not use the surfactants or other templates in the preparation of CdS nanoparticles.
The experiments were carried out at 180
C for 5 h. The morphology of the resul-
tant CdS nanoparticles could be determined by shifting the reactions between
thermodynamically and kinetically controlled parameters
[194]
.
