Selective synthesis of uniform iron oxide nanoparticles: Influence of precursors, temperature, and surfactant concentration.

In nanoparticle (NP) synthesis, controlling the size and shape of the NPs is crucial for tuning the intrinsic properties. Generally, the morphology of colloidal NPs can be controlled by adjusting various parameters such as the precursor concentration, reaction temperature, time, and surfactant ligands. In this study, selective iron oxide nanoparticle (IONP) synthesis, yielding size and shape uniformity, was developed by modulating the iron precursors. In the IONP synthesis with Fe(acac)3, the shape of the NPs was controlled from irregular to spherical depending on the reaction temperature when the IONPs were synthesized with oleylamine (OLAM) and oleic acid (OA). When the reaction temperature was set above 280 ∘ C, the size of the IONPs was 20 nm, with a narrow size distribution. The sizes of the IONPs synthesized using Fe(acac)3 and octadecene (ODE) were dramatically influenced by the concentration of OA (20–50 nm). As the concentration of OA increased, the size of the IONPs decreased, which might be due to the control of NP growth and prevention of Ostwald ripening induced by OA. When Fe(CO)5 was used as the iron precursor, OA played a crucial role in the synthesis of the IONPs, similar to that in the synthesis of Fe(acac)3. The size of the IONPs synthesized with Fe-oleate was tuned from 5 nm to 15 nm depending on the vacuum temperature used in the pretreatment process. These results provide insight into the synthesis of uniform IONPs based on the synthesis parameters such as the iron precursor, temperature, and ligand concentration. [ABSTRACT FROM AUTHOR]