Obtaining of Luminescent Sulfur Nanoparticles in the L-Cysteine–Citrate–Sodium Sulfide System

An obtaining of sulfur nanoparticles by hydrothermal method in aqueous solution of L-cysteine, citrate ions, and sodium sulfide is proposed. The optical properties of the obtained sulfur nanoparticles have been studied by UV-Visible absorption and photoluminescence spectroscopies. Transmission and scanning electron microscopies and atomic force microscopy indicate that sulfur nanoparticles are quasi-spherical, their diameter depends on heat treatment time reaching an average size of 28 nm after 8 h of heating at 378 K. The nanoparticles exhibit photoluminescence in the range from 388 to 515 nm depending on the excitation wavelength. The obtained colloid systems have lasting sedimentation stability and high photoluminescence intensity, which make them promising for further wide application.