科研之友
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摘要
A facile organic route has been developed to synthesize CdTexSe1-x nanocrystals (NCs) using stearic acid as a capping agent. Because of growth kinetics of CdTe and CdSe, the molar ratio of Te/Se enables CdTexSe1-x NCs with various morphologies. By increasing the Te/Se ratio, the morphology of the NCs can be adjusted from tetrahedron to tetrapod. This is ascribed to the energy difference between wurtzite and the zinc-blende structures, which determines the nucleation and growth processes of the NCs. The diameters of the branches of tetrapod were 4-6 nm and their lengths were 7-20 nm. The CdTexSe1-x NCs revealed near-infrared (NIR) range (700-800 nm) photoluminescence (PL). The PL properties of the resulting NCs are strongly dependent on preparation conditions such as the molar ratio of Te/Se as well as the reaction temperature and time. In the cases of various reaction temperature (120-260 degrees C), the NCs revealed adjusted PL peak wavelength from visible to NIR range and narrow PL spectra. In addition, even though a high Te/Se molar ratio (0.67) was used, the CdTexSe1-x NCs revealed improved stability compared with CdTe NCs. Being coated with a composite CdyZn1-yS shell, the PL intensity was drastically enhanced. The approach described here is utilizable to the fabrication of other semiconductor NCs with various morphologies. Because of the adjusted morphologies, tunable NIR range emission, and high stability of these composite NCs, we will focus on their applications such as solar cell and biolabeling.
- 出版日期2012-8
- 单位济南大学
