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

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
M. Sajjad ◽  
V. Makarov ◽  
M. S. Sultan ◽  
W. M. Jadwisienczak ◽  
B. R. Weiner ◽  
...  

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.

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 844 ◽  
Author(s):  
Quanrun Liu ◽  
Jingjie Zhang ◽  
He He ◽  
Guangxu Huang ◽  
Baolin Xing ◽  
...  

Coal tar pitch (CTP), a by-product of coking industry, has a unique molecule structure comprising an aromatic nucleus and several side chains bonding on this graphene-like nucleus, which is very similar to the structure of graphene quantum dots (GQDs). Based on this perception, we develop a facile approach to convert CTP to GQDs only by oxidation with hydrogen peroxide under mild conditions. One to three graphene layers, monodisperse GQDs with a narrow size distribution of 1.7 ± 0.4 nm, are obtained at high yield (more than 80 wt. %) from CTP. The as-produced GQDs are highly soluble and strongly fluorescent in aqueous solution. This simple strategy provides a feasible route towards the commercial synthesis of GQDs for its cheap material source, green reagent, mild condition, and high yield.


2015 ◽  
Vol 3 (23) ◽  
pp. 5910-5917 ◽  
Author(s):  
Chan Wang ◽  
Yagang Yao ◽  
Qijun Song

The dual optical and magnetic properties of the synthesized Fe3O4@AuNCs were applicable to cancer diagnosis by fluorescence and MR-based imaging.


2018 ◽  
Vol 6 (39) ◽  
pp. 10502-10512 ◽  
Author(s):  
Brandon Azeredo ◽  
Anne Carton ◽  
Cédric Leuvrey ◽  
Céline Kiefer ◽  
Dris Ihawakrim ◽  
...  

A ZnO/PBA/Fe3−δO4 nanocomposite displays enhanced magnetic and optical properties as a result of dual synergy.


2019 ◽  
Vol 114 (7) ◽  
pp. 072403 ◽  
Author(s):  
Qi Zhao ◽  
Qing Lu ◽  
Yi Liu ◽  
Mingzhe Zhang

Catalysts ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 438 ◽  
Author(s):  
Fei Li ◽  
Ming Li ◽  
Yi Luo ◽  
Ming Li ◽  
Xinyu Li ◽  
...  

In this study, nitrogen-doped graphene quantum dots (N-GQDs) and a TiO2 nanocomposite were synthesized using a simple hydrothermal route. Ammonia water was used as a nitrogen source to prepare the N-GQDs. When optically characterized by UV-vis, N-GQDs reveal stronger absorption peaks in the range of ultraviolet (UV) light than graphene quantum dots (GQDs). In comparison with GQDs/TiO2 and pure TiO2, the N-GQDs/TiO2 have significantly improved photocatalytic performance. In particular, it was found that, when the added amount of ammonia water was 50 mL, the content of pyridinic N and graphitic N were as high as 22.47% and 31.44%, respectively. Most important, the photocatalytic activity of N-GQDs/TiO2-50 was about 95% after 12 min. The results illustrated that pyridinic N and graphitic N play a significant role in photocatalytic performance.


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