Login Register
 
Home Accepted Papers
The photo-physical and morphological properties of PVP-capped ZnS quantum dots synthesized via aqueous method
Paper ID : 2439-UFGNSM13-FULL (R1)
Authors:
Abstract:
In this work, the ZnS nanoparticles were synthesized via an aqueous method and the effect of polyvinylpyrrolidone (PVP) as organic capping agent in different concentrations on the photo-physical properties was studied. The comprehensive characterization methodes such as X-ray diffraction (XRD), fourier transform infrared (FTIR), scanning electron microscopy (SEM), UV-Visible absorption and photoluminescence (PL) spectra were used to analyze the prepared nanoparticles. In order to control particles size by limiting the growth of the particles after the nucleation and also to provide a functional group on the surface which can be further conjugated to bio-cells, PVP as an organic agent was used. The XRD analysis revealed that the nanocrystals have cubic zinc blende structure and the crystallite size of the products was estimated about 2-3 nm using Scherer’s equation. The SEM micrograph showed uniform morphology and relatively regular fine grains with near spherical shape. Also, the FTIR spectrum confirmed the presence of PVP on the surface of ZnS nanoparticles. PL investigations indicated that emission of capped ZnS samples become more intensive and shifts towards smaller wavelength and it has maximum intensity in concentration of 1.5% wt capping agent. The UV-Visible absorption results illustrated that optical band gap of spherical capped nanoparticles have higher energy compared to uncapped sample and the band gap can be widened up to 4.05 eV (correspond to capped ZnS nanoparticles) from 3.67 eV (correspond to bulk ZnS), which is due to quantum confinement effect.
Keywords:
Photoluminescence, Quantum Dot, Capping agent, Aqueous method
Status : Paper Accepted (Poster Presentation)