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

Abstract

e 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 (Fe 3 O 4 ) 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. e hexagonal structures and lattice fringes associated with the C-C bond in GQDs were clearly identifiable. e structural and optical changes in GQDs and GQDsFe 3 O 4 NC samples induced by UV light were investigated by the absorption and emission spectroscopy over the deep UV-visible spectral range. e photoluminescence spectra have shown subband π→π * transitions in GQDs-Fe 3 O 4 NC. Magnetic properties of the GQDs-Fe 3 O 4 NC samples have shown room temperature ferromagnetism induced by pure Fe 3 O 4 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.

Synthesis of graphene quantum dots and their applications in drug delivery

“…Due to the unique structure and excellent properties of GQDs, researchers have reported more and more preparation methods based on the popular techniques, such as chemical vapor deposition (CVD) [33,77] and pulsed laser ablation (PLA) [78,79].…”

Observation of critical magnetic behavior in 2D carbon based composites

“…Size and shape have always been crucial for tuning magnetic properties as predicted by theoretical calculations. 121 For instance, cutting of a graphene sheet into two parts results in the formation of zigzag or armchair edges which alters the 126 Similarly, zigzag graphene nano-akes (GNFs) showed strong edge magnetism. On increasing the system size, the zigzag edge states in the GNFs become more localized and stronger.…”

“…It was predicted by Sajjad and coworkers that the spin polarized edges of the GQDs and the magnetic Fe 3 O 4 nanoparticles induced ferromagnetism in Fe 3 O 4 –GQDs composites. 126 Similarly, zigzag graphene nanoflakes (GNFs) showed strong edge magnetism. On increasing the system size, the zigzag edge states in the GNFs become more localized and stronger.…”

Superparamagnetic Iron Oxide Nanoparticles with Large Magnetic Saturation and High Particle Photon Counts for Super-Resolution Imaging of Lysosomes

“…A new class of nanometer-sized cationic polymersomes loaded with SPIONs and quantum dots was fabricated by Wen et al Yoon et al reported complex cobalt ferrite magnetic nanoparticles coated with an amorphous silica shell containing fluorescent organic dyes for optical imaging . Sajjad et al engineered graphene quantum dot iron oxide nanocomposites using a pulsed laser discharge technique to tailor the material’s optical and magnetic properties for biomedical and optoelectronic applications . Highly monodisperse particles composed of a magnetic silica core and a fluorescent polymer shell were synthesized by Nagao et al…”

“…24 Sajjad et al engineered graphene quantum dot iron oxide nanocomposites using a pulsed laser discharge technique to tailor the material's optical and magnetic properties for biomedical and optoelectronic applications. 25 Highly monodisperse particles composed of a magnetic silica core and a fluorescent polymer shell were synthesized by Nagao et al 26 Unfortunately, even with the larger particle, the magnetic saturation was still found to be much less as compared to bare SPIONs. Only a few examples exist in the literature for smaller SPIONs with large magnetic saturation values and fluorescent properties.…”