Microwave-assisted synthesis of PbS nanostructures

The synthesis of PbS nanostructures by microwave irradiation of single source precursor compounds in ethyleneglycol medium is reported. Pb(II) bis(N-ethyl-N-phenyldithiocarbamate) and Pb(II) bis(N-butyl-N-phenyldithiocarbamate) represented as complexes (1) and (2) respectively were utilised. The prepared PbS nanostructures were characterized using X-ray diffraction (XRD), Transmission electron microscopy (TEM), and absorption spectroscopy. The results showed that complex (1) can project the formation of nanorod with (111) basal plane, while (2) project the formation of nanocube with (001) basal plane. The formation of different morphologies in ethylene glycol may also be due to the selective binding to specific crystallite facets of the PbS through the hydroxyl groups of ethylene glycol. In the nanorod, the selective stabilization of the (111) face of PbS, resulted in anisotropic growth along the (100) face. The high resolution TEM images showed distinct lattice fringes which confirmed the crystallinity of the nanostructures. The band gap energies were obtained as 1.10 and 1.12 eV for the nanorods and nanocubes respectively, a significant blue shift from the bulk value (0.4 eV) which could be ascribed to quantum confinement effect. The result established the significant effect of the precursor type on the morphologies of the PbS.