Study on the structure of PbS nanoparticles coated with dialkyldithiophosphate

PbS nanoparticles modified with di-n-hexadecyldithiophosphate (DDP) were prepared by the chemical surface modification method. The structure of the PbS nanoparticles coated with DDP was investigated by means of infrared spectroscopy (ir), x-ray photoelectron spectroscopy (XPS), x-ray diffraction (XRD), transmission electron microscopy (TEM), and ³¹P nuclear magnetic resonance spectroscopy (³¹P NMR). The thermal stability of DDP coating on the PbS nanoparticles was compared with that of pyridinium di-n-hexadecyldithiophosphate (PyDDP) using a thermogravimetric analyzer (TGA). It was found that coated PbS nanoparticles had an average diameter of about 5 nm. Surface modification with DDP prevented water adsorption and effectively improved the dispersive capacity and antioxidative stability of PbS nanoparticles. The thermal stability of DDP coating on the surface of nano-PbS particles was higher than that of modifier PyDDP because of the chemical interaction between PyDDP and PbS during the coating process.