Rapid Synthesis of Highly Dispersed and Stable Oleic Acid Capped Lead Sulphide Nanoparticles

We report a simple and rapid process for synthesis of oleic acid capped lead sulphide nanoparticles using lead acetate–thiourea complex. Thermal decomposition of oleic acid capped complex provides controlled formation of lead sulphide nanoparticles with uniform size, shape, and distribution. Optical absorption spectrum of oleic acid capped lead sulphide nanoparticles shows strong blue shift due to size quantization with band gap of around 1.65 eV. The morphology, crystallinity, capping nature and phase composition of capped lead sulphide nanoparticles are examined by transmission electron microscopy, selective area electron diffraction, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results show that oleic acid capped lead sulphide nanoparticles with an average diameter of about 10 nm are crystalline in nature and oleic acid is absorbed chemically on nanoparticle's surface instead of physical absorption. The oleic acid capping layer effectively prevents surface oxidation of the nanoparticles. Size distribution studies reveal the high duration stability of oleic acid capped lead sulphide nanoparticles without any agglomeration at room temperature.