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Shape and phase control of CdS nanocrystals using cationic surfactant in noninjection synthesis.

Zou Y, Li D, Yang D - Nanoscale Res Lett (2011)

Bottom Line: Monodispersed CdS nanocrystals with controllable shape and phase have been successfully synthesized in this study by adding cationic surfactant in noninjection synthesis system.With the increase of the amount of cetyltrimethylammonium chloride (CTAC) added, the shape of the CdS nanocrystals changed from spherical to multi-armed, and the phase changed from zinc-blende to wurtzite.In addition, it was found that the multi-armed CdS nanocrystals lost quantum confinement effect because of the increase of the size with the increase of the concentration of CTAC.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China. mselds@zju.edu.cn.

ABSTRACT
Monodispersed CdS nanocrystals with controllable shape and phase have been successfully synthesized in this study by adding cationic surfactant in noninjection synthesis system. With the increase of the amount of cetyltrimethylammonium chloride (CTAC) added, the shape of the CdS nanocrystals changed from spherical to multi-armed, and the phase changed from zinc-blende to wurtzite. It was found that halide ion Cl- plays a key role in the transformation, and other halide ions such as Br- can also induce similar transformation. We proposed that the strong binding between Cd2+ and halide ions reduced the reactivity of the precursors, decreased the nuclei formed in the nucleation stage, and led to the high concentration of precursor in the growth stage, resulting in the increase of size and phase transformation of CdS nanocrystals. In addition, it was found that the multi-armed CdS nanocrystals lost quantum confinement effect because of the increase of the size with the increase of the concentration of CTAC.

No MeSH data available.


Related in: MedlinePlus

XRD patterns of the CdS nanocrystals obtained with different amounts of CTAC added. A phase transformation from zinc blende to wurtzite was exhibited with the increase of the amount of CTAC.
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Figure 2: XRD patterns of the CdS nanocrystals obtained with different amounts of CTAC added. A phase transformation from zinc blende to wurtzite was exhibited with the increase of the amount of CTAC.

Mentions: To investigate the morphology transformation induced by the addition of CTAC, XRD analysis was employed for determining the crystal structure of the CdS nanocrystals. The XRD patterns shown in Figure 2 indicate that the phase transformation from zinc blende to wurtzite occurred as the shape of the CdS nanocrystals varied from spherical to multi-armed. When no CTAC was used, the CdS nanocrystals with pure zinc-blende structure were synthesized, which has also been shown in the previous study [19]. With the increase of the amount of CTAC added, the characteristic diffraction peaks of (100), (101), (102), and (103) planes corresponding to the hexagonal wurtzite structure became more and more distinct, revealing the phase transformation from zinc-blende to wurtzite. Meanwhile, the narrowing of the diffraction peaks also indicates the increase of the size of the CdS nanocrystals according to the Scherrer formula, which is consistent with the results obtained from the TEM images.


Shape and phase control of CdS nanocrystals using cationic surfactant in noninjection synthesis.

Zou Y, Li D, Yang D - Nanoscale Res Lett (2011)

XRD patterns of the CdS nanocrystals obtained with different amounts of CTAC added. A phase transformation from zinc blende to wurtzite was exhibited with the increase of the amount of CTAC.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211467&req=5

Figure 2: XRD patterns of the CdS nanocrystals obtained with different amounts of CTAC added. A phase transformation from zinc blende to wurtzite was exhibited with the increase of the amount of CTAC.
Mentions: To investigate the morphology transformation induced by the addition of CTAC, XRD analysis was employed for determining the crystal structure of the CdS nanocrystals. The XRD patterns shown in Figure 2 indicate that the phase transformation from zinc blende to wurtzite occurred as the shape of the CdS nanocrystals varied from spherical to multi-armed. When no CTAC was used, the CdS nanocrystals with pure zinc-blende structure were synthesized, which has also been shown in the previous study [19]. With the increase of the amount of CTAC added, the characteristic diffraction peaks of (100), (101), (102), and (103) planes corresponding to the hexagonal wurtzite structure became more and more distinct, revealing the phase transformation from zinc-blende to wurtzite. Meanwhile, the narrowing of the diffraction peaks also indicates the increase of the size of the CdS nanocrystals according to the Scherrer formula, which is consistent with the results obtained from the TEM images.

Bottom Line: Monodispersed CdS nanocrystals with controllable shape and phase have been successfully synthesized in this study by adding cationic surfactant in noninjection synthesis system.With the increase of the amount of cetyltrimethylammonium chloride (CTAC) added, the shape of the CdS nanocrystals changed from spherical to multi-armed, and the phase changed from zinc-blende to wurtzite.In addition, it was found that the multi-armed CdS nanocrystals lost quantum confinement effect because of the increase of the size with the increase of the concentration of CTAC.

View Article: PubMed Central - HTML - PubMed

Affiliation: State Key Laboratory of Silicon Materials and Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China. mselds@zju.edu.cn.

ABSTRACT
Monodispersed CdS nanocrystals with controllable shape and phase have been successfully synthesized in this study by adding cationic surfactant in noninjection synthesis system. With the increase of the amount of cetyltrimethylammonium chloride (CTAC) added, the shape of the CdS nanocrystals changed from spherical to multi-armed, and the phase changed from zinc-blende to wurtzite. It was found that halide ion Cl- plays a key role in the transformation, and other halide ions such as Br- can also induce similar transformation. We proposed that the strong binding between Cd2+ and halide ions reduced the reactivity of the precursors, decreased the nuclei formed in the nucleation stage, and led to the high concentration of precursor in the growth stage, resulting in the increase of size and phase transformation of CdS nanocrystals. In addition, it was found that the multi-armed CdS nanocrystals lost quantum confinement effect because of the increase of the size with the increase of the concentration of CTAC.

No MeSH data available.


Related in: MedlinePlus