Study On The Preparation Of Several Nano-semiconductors Using Ionic Liquids

There are many methods to prepare nanomaterials, such as gas, template, microwave, however, some of them might involve versatile organic solvents, and the others might need harsh reaction conditions, which will cause pollution to the environment as well as increase the cost. Therefore, environment-friendly ionic liquid can be used as the reaction medium instead of the versatile organic solvents. We are able to develop simple, environment-friendly process by developing nano-material preparation in ionic liquids. By now, a series of nanomaterials, such as nano-particle, nano-plates, nano-stick, nano-fiber, have been prepared successfully in ionic liquids, which has made the study on this field to be a hot research area. Microwave heating method draw widespread attention for rapid heating rate, short reaction time, uniform temperature distribution and the more crystallinity. Therefore, the various nano-materials were prepared by microwave heating method in our research.1. Using ionic liquid as precursor, the CdS nano-structures and the ZnS micro-spherical nanoparticles were synthesized by microwave heating method in a very short time. The two kinds of nano-crystals were observed by the X-ray powder diffraction analysis, and the lattice constant of them calculated by XRD exhibits a high degree of consistency with standard cards involved; EDS analysis showed the composition of the two products which was in line with the chemical formula composition; their morphology were characterized by FESEM and the impact on the morphology of nanocrystalline were studied including reaction time, reaction temperature, reactant concentration, further more, its possible mechanism was presented by the analysis of experimental results.2. Hierarchical PbTe structures were prepared by microwave rapid heating and the growth rule with different reaction conditions was researched. The composition of the PbTe was detected by XRD and the morphology was observed by FESEM, moreover, the product formation process was roughly analyzed according to these results. The synthesized PbTe presented a variety of morphologies including the funnel-like structure, flower-like structure and the dendritic structure. It was studied that the impact of the process of reaction and the product structure and performance through adding ionic liquid, and showed that the different morphologies with more regular crystal and crystal surface can easily get after adding ionic liquid into the system. Moreover, it was proved that the addition of ionic liquid has some impact on the formation of hierarchical structure, and the octahedral structure of the product was produced by adding large amount of ionic liquid. Finally, the electrochemistry properties of PbTe nanocrystals were tested.3.The Te nanowires and Te nanorods were prepared by microwave heating method and characterized by XRD, SEM and HRTEM; moreover, the PbTe nano wires and PbTe nanorods were also produced respectively and also characterized by XRD, SEM and HRTEM. Finally, the electrochemistry properties of PbTe nanowires and PbTe nanorods were tested and results appeared that PbTe nanowires possessed the oxidation peak and the reduction peak. There is an oxidation peak and no reduction peak in the sample of the PbTe nanorods. Compared to the CV curves of the PbTe nanorods, the oxidation peak appears the higher electric potential, indicating that the PbTe in this sample is more easily oxidized. Reduction peak does not appear for the difficulty of the PbTe to be reduced.