Preparation and growth mechanism of lead telluride nanocrystals by a modified molten composite-hydroxides method.

ABSTRACT

PbTe nanocrystals were prepared by a modified molten composite-hydroxides method at 180 degrees C for different times, using Pb(NO3)2 and TeO2 as starting materials and KBH4 as a reductant. The nanocrystal structure and morphologies of the synthesized products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution TEM (HRTEM), respectively. The results showed that the reaction time has a significant influence on the size and shape of the as-prepared PbTe nanocrystals. As the reaction time increased, the as-prepared products were eventually transformed from nanomaterials (nanocubes, nanorods, and nanosheets) to microcrystals with different morphologies (microcubes, mciroprisms, and microplates). The formation mechanism of the PbTe was proposed, and a one-dimensional oriented attachment growth process combined with two-dimensional oriented attachment growth process was suggested for the growth of nanorods and nanosheets.