Highly Luminescent ZnS Nanoparticles Obtained by Microwave Heating

Abstract

We report the results of the synthesis and characterization of highly luminescent ZnS nanoparticles obtained by microwave heating working at 905 W during 60 sec. The products were characterized by UV-vis spectroscopy, photoluminescent spectroscopy, X-ray diffraction and atomic force microscopy. Different morphologies were observed by AFM, nanoparticles (average diameter = 100 nm) and nanoislands (micrometer size). As the content of S ²⁻ and Zn ²⁺ decreases, the band edge emission becomes higher and the photoluminescent intensity increases, finding a quantum yield of 70%, and both of these properties exhibit a blue shift due to the reduction in particle size. The X-ray diffraction analysis indicates the presence of ZnS in cubic sphalerite form. Microwave heating includes the ability to quickly reach reaction temperatures and a straightforward process control, thus making quantum dot materials with quantum yield (QYs) of 70%, accessible to an increased number of research labs.

Keywords:

• highly luminescent
• microwaves
• nanoparticles
• ZnS

The authors express their gratitude to PAICYT for economic support and Sol-Gel Laboratory at Facultad de Ciencias Químicas also Materials Laboratory at Facultad de Ingeniería Mecánica y Eléctrica for the atomic force microscopy analysis.