Synthesis of PbTe and PbSe nanoparticles under the influence of hydrochloric acid and carbon dioxide

Parameters that influence the growth of nanomaterials have been extensively studied. Recent studies have shown that the addition of halogen can influence the growth mechanism and properties of nanomaterials. We have used simple reduction thermolysis method to synthesize hexadecylamine (HDA) and oleylamine (OLA) capped PbTe and PbSe nanoparticles. We added a small amount of hydrochloric acid (HCl) and bubbled carbon dioxide (CO2) to determine their effect on the particle morphology. For PbTe the particle morphology was determined by the capping group with the HDA capped PbTe in the form of rods whereas the OLA capped particles were hexagonal in shape. The addition of HCl gave shorter rods in the case of HDA PbTe while in the case of the OLA capped PbTe regular shaped hexagonal cubes were observed. The bubbling of CO2 resulted in the change of shape from rods to cubes. Both the HDA and OLA capped PbSe nanoparticles were oblate in shape. The bubbling of CO2 into the reaction system resulted in PbSe nanoparticles with a hexagonal morphology. Powder X-ray diffraction studies revealed a pure cubic phase for both PbTe and PbSe nanomaterials. The optical absorption spectra for both HDA /OLA capped PbTe and PbSe showed evidence of quantum confinement.