Luminescence of ZnS:Cu particles modified by shungite nanocarbon

This paper presents a study of the luminescence properties of the commercial phosphor ZnS:Cu modified with nanoparticles of shungite carbon. It shows that even a small amount of the modifying additive causes substantial surface darkening of the phosphor and reduces the reflectance at a wavelength of 490 nm. A number of competing processes are observed: a reduction of the luminance of the electroluminescence because part of the emitted light is absorbed, and an increase of the luminance, probably because the electric field is concentrated on the phosphor particles. Besides altering the luminance, such modification alters the electroluminescence spectra. Modification by shungite-carbon nanoparticles is thus promising from the viewpoint of directed adjustment of the characteristics of commercial phosphors, and optimizing the modification conditions makes it possible to obtain luminescence whose luminance exceeds that in unmodified samples. (C) 2017 Optical Society of America