Abstract
Thermal decomposition is a promising route for the synthesis of magnetic nanoparticles. The simplicity of the synthesis method is counterbalanced by the complex chemistry of the system such as precursor decomposition and surfactant-reducing agent interactions. Control over nanoparticle size is achieved by adjusting the reaction parameters, namely, the precursor concentration. The results, however, are conflicting as both an increase and a decrease in nanoparticle size, as a function of increasing concentration, have been reported. Here, we address the issue of size-controlled synthesis via the precursor concentration. We synthesized iron oxide nanoparticles with sizes from 6 nm to 24 nm with narrow size distributions. We show that the size does not monotonically increase with increasing precursor concentration. After an initial increase, the size reaches a maximum and then shows a decrease with increasing precursor concentration. We argue that the observation of two different size regimes is closely related to the critical role of the amount of surfactant. We confirm the effect of surfactant amount on nucleation and growth and explain the observed trend. Furthermore, we show that the nanoparticles show size-dependent but superior superparamagnetic properties at room temperature.
Original language | English |
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Pages (from-to) | 6694-6702 |
Number of pages | 9 |
Journal | CrystEngComm |
Volume | 19 |
Issue number | 44 |
DOIs | |
Publication status | Published - 2017 |
Funding
K. A. acknowledges the Alexander von Humboldt Foundation for the funding provided in the framework of the Sofja Kovalevskaja Award, endowed by the Federal Ministry of Education and Research, Germany. The authors acknowledge the support from the Max-Planck Institute for Polymer Research (Mainz, Germany) and the technical help of Dr. Ingo Lieberwirth, Michael Steiert, Verona Maus, Michelle Beuchel, Ann-Kathrin Schönbein and Elham khodabakhshi. Open Access funding provided by the Max Planck Society.
ASJC Scopus subject areas
- General Chemistry
- General Materials Science
- Condensed Matter Physics