Lead sulfide (PbS) nanoparticles were synthesized at room temperature via a simple chemical reaction. In this work, thiophenol was used as the capping agent and sodium sulfide was used as a sulfur source. The products were characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, ultraviolet-visible, photoluminescence and Fourier transform infrared spectroscopy. Electron microscopy studies reveal that synthesis of PbS nanoparticles using no capping agent produces PbS nanoparticles with relatively large size, whereas adding thiophenol leads to the production of nano-sized PbS particles. We found that electronic absorption spectra as well as particle sizes depend on the used capping agents. Compared with bulk PbS, the absorption spectra of the obtained PbS nanoparticles exhibit a blue shift, which can be attributed to the quantum confinement of charge carriers in the nanoparticles.
