Fabrication of symmetric hierarchical hollow PbS microcrystals via a facile solvothermal process

Symmetric hierarchical hollow PbS structures consisting of nanowalls were successfully fabricated by a facile solvothermal process in ethylenediamine at 120 C for 12 h, employing lead acetate trihydrate and dithizone as precursors; the thickness of the nanowalls is about 80 nm. No surfactants or other templates were used in the process. The synthesized product was characterized by X-ray powder diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), ultraviolet-visible spectrometer (UV-vis), near-infrared absorption spectroscopy (near-IR), and fluorescence spectrophotometer. The effect of the reaction conditions on the size and morphologies of PbS structures was investigated. The results show that the temperatures, solvent, and sulfur sources are crucial factors on the morphologies and sizes of the symmetric hierarchical hollow PbS microcrystals. A possible growth mechanism of hierarchical hollow PbS structures is presented. UV-vis absorption spectrum holds a weak peak at 253 nm; the near-infrared absorption spectrum of PbS microcrystals has the two absorption peaks centered at 9613 cm(-1) (1040 nm) and 6771 cm(-1) (1477 nm), showing a blue shift compared with the bulk PbS (similar to 3020 nm). And the fluorescence spectrum of PbS microcrystals consists of an emission peak with a maximum at 305 nm. These PbS microcrystals may have potential applications in the fundamental study of nanostructures as well as fabricating nanodevices.