| CdTe is an important engineering-related II-VI semiconductor material. CdTe semiconductor nanocrystals have attracted great attention in the past decades due to its unique high optical absorption coefficient, and the advanced photovoltaic properties, which show great potential luminescence and photoelectronic application.In this paper, EG, EG-Glycerin, and EG/Terpineol solvent systems using cadmium nitrate and sodium tellurite as precursors were applied to synthesize CdTe nanocyrstals. The synthesized products were characterized by XRD, SEM, TEM, HRTEM, EDS, IT-IR and UV-vis. The influence of preparation conditions, such as complexing agent, injection tempetature, refluxing temperature, Cd /Te molar ratio, different surfactants and their amounts was investigated.Experimental results showed that in EG system, the CdTe nanocrystals with wurtzite and zinc blende mixed phase tend to be formed, in which the wurtzite proportion could be dominanted by changing complexing agent, injection tempetature, refluxing temperature, Cd /Te molar ratio. Pure zinc blende CdTe was synthesized with TEA as complexing agent, and the wurtzite and zinc blende mixed CdTe nanocrystals was synthesized without complexing agent. With increasing injection temperature, the metastable wurtzite pahse and crystal size of CdTe nanocrystals gradually decreased. The best injection and refluxing temperature are 19℃0 and 168℃respectively. When the Te precursor solution with Cd/Te molar ratio of 1.0 was injected to the Cd based reaction solution, pure zinc blende CdTe nanocrystals was prepared. But when the Cd precursor solution with Cd/Te molar ratio of 1.0 was injected to the Te based reaction solution, wurtzite and zinc blende mixed CdTe nanocrystals was formed. In EG- Glycerin system, quick injection is beneficial to the formation of zinc blende CdTe nanocrystals, while the bi-phase mixed CdTe nanocrystals is easy to be synthesized by slow injection. In EG/ Terpineol system, the synthesized CdTe nanocrystals exhibited the best dispersion as the EG/ Terpineol volume ratio is 4.0.Influence of the four surfatants CTAB, PEG400, PEG2000 and PVP on synthesis process of CdTe nanocrystals was also studied. The results show that PVP with concentration of 1g/L displayed the best disersion effect to the synthesized nanocrystals. When CdTe nanocrystals was dispersed in ethyl alcohol absolute solvent with PVP adding, the CdTe nanocrystal suspension had the best dispersion stability, that could be used to fabricate CdTe thin film. |
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