Synthesis, Optical, and Magnetic Properties of Graphene Quantum Dots and Iron Oxide Nanocomposites

Abstract

The combination of nanomaterial graphene quantum dots (GQDs) with magnetic nanoparticles offers a unique set of optical and magnetic properties for future energy and medical applications. We report on the synthesis and engineering of GQDs and iron oxide (Fe3O4) nanocomposites (NCs) by using a pulsed laser discharge technique. High-resolution transmission electron microscopy (HRTEM) images showed a high yield of pure GQDs with 2-10 nm diameter. The hexagonal structures and lattice fringes associated with the C-C bond in GQDs were clearly identifiable. The structural and optical changes in GQDs and GQDs-Fe3O4 NC samples induced by UV light were investigated by the absorption and emission spectroscopy over the deep UV-visible spectral range. The photoluminescence spectra have shown subband π→π∗ transitions in GQDs-Fe3O4 NC. Magnetic properties of the GQDs-Fe3O4 NC samples have shown room temperature ferromagnetism induced by pure Fe3O4 nanoparticles and from the substantial spin polarized edges of GQD nanoparticles. It is concluded that the observed optical and magnetic properties could be further tailored in the studied nanocomposites for prospective medical applications.