Generation of ZnS Nanostructures with Modified Chemical Surface

Abstract

Semiconductor nanomaterials like zinc sulphide have interesting potential applications, consequent to their size-dependent optical properties. These nanostructures can be used on optoelectronic, photocatalysis, solar cells, and fluorescence microscopy, among others. Due to the great use of these nanoparticles in society, there is great concern in the scientific community about the potential negative interaction of these nanomaterials in aquatic environments. The present research was conducted on generation of nanostructures of ZnS with modified surface. This work had three goals: 1) morphological, compositional, and optical characterization of ZnS nanoparticles; 2) surface chemical modification of ZnS nanoparticles with biocompatible molecules; and 3) interaction studies of ZnS nanoparticle. A main absorption peak at ∼365-375nm range and a trap emission peak at ∼425nm were observed in the emission spectrum of ZnS nanoparticles synthesized at 160°C and 180°C and 30 minutes of reaction. The morphology and the size of ZnS were carried out by High Resolution Transmission Electron Microscopy (HR-TEM). In this way, nanoparticles were spherical and with a size less than 10nm. Energy Dispersive X-Ray Spectroscopy evidenced the chemical composition of produced nanostructures. The chemical modification of ZnS nanostructures was corroborated by Infrared Spectroscopy Analysis. The interaction studies of ZnS nanoparticles were studied in aquatic systems in presence of marine organisms. The concentrations of nanoparticles for these studies ranged from 0ppm to 300ppm and the contacting time with the living organisms was 24 and 48 hours. Also, Zn²⁺ (as Zinc nitrate and Zinc sulphate) was used as comparison purposes. Zinc sulphide nanoparticles covered with thioglycolic acid and L-cysteine evidenced a negative interaction at concentrations higher than 10ppm.