Structural, optical and photocatalytic studies of hexadecylamine-capped lead sulfide nanoparticles

Abstract

Hexadecylamine-capped PbS nanoparticles were prepared from lead(II) complexes of dibenzyl dithiocarbamate (Dibzydtc) [PbS 1], imidazolyl dithiocarbamate (Imdtc) [PbS 2], 2-oxo-pyrrolidine dithiocarbamate (Pydtc) [PbS 3], diallyl dithiocarbamate (Diallyldtc) [PbS 4], and dihexyl dithiocarbamate (Dihexdtc) [PbS 5], at 120 °C. Powder X-ray diffraction patterns of the PbS nanoparticles are indexed to the face-centered cubic phase. The average particle sizes obtained from the TEM images are 19.04 ± 5.85 nm for PbS 1, 6.94 ± 1.71 nm PbS 2, 18.77 ± 3.37 nm PbS 3, 2.93 ± 2.20 nm PbS 4 and 22.02 ± 6.68 nm for PbS 5. The PbS nanoparticles are spherical in shape except for PbS 1 and PbS 3 with cubic shapes. The bandgap energies range from 3.0 to 3.8 eV and PbS 1 has the lowest bandgap of 3.0 eV while PbS 3 has the highest bandgap of 3.8 eV. The bandgaps are blue-shifted in comparison to the absorption band edges due to quantum size effect. The photocatalytic degradation of bromothymol blue by the as-prepared PbS nanoparticles showed highest degradation efficiency of 66% for PbS 3.