Green synthesis and characterisation of spherical PbS luminescent micro- and nanoparticles via wet chemical technique

In this research, the authors present a simple and surfactant free procedure for the synthesis of spherical lead sulphide (PbS) micro and nano particles. The X-ray diffraction (XRD) analysis showed that the crystal structure of PbS nanocrystals (NCs) was in its cubic phase. Also, the average crystallite size using Scherrer's formula was similar to 13 nm and the calculated lattice constant using Bragg's equation was 0.5950 nm, which was very close to the value in the standard card (JCPDS Card File No. 5-592). In addition, the samples were characterised by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray analyser (EDX), photoluminescence (PL) and Fourier transform infrared (FTIR). The SEM and TEM images revealed that the synthesised particles had a well defined spherical morphology. Finally, the PL study showed that the emission spectrum was a strong and narrow band with high intensity centred at 655 nm which confirmed the high quality luminescence properties of the synthesised PbS NCs.