Iron Oxide Nanoparticles with Controlled Size and Shape

Controlling the shape of Fe₃O₄ particles is still a big challenge. It has been shown that the SAR value for hyperthermia measurements, has been related to the magnetic anisotropy of the nanoparticles which depends on their size and shape [1]. Therefore, it’s very important to control the shape and the size of Fe₃O₄ nanoparticles precisely.
Here, a simple approach for synthesizing Fe₃O₄ nanoparticles is studied. The synthesis takes place in a oleylamine/dodecylamine solution, using Fe(acac)₃ as the Iron precursor. The XRD measurements, show a pure Fe₃O₄ phase. It is observed that the nanoparticles made with Oleylamine-Oleic acid mixture, are completely spherical; however, the shape of nanoparticles synthesized with Dodecylamine-Octadecene mixture, could be easily changed from spherical to facet. It is shown that by decreasing the amount of dodecylamine from 10 to 2.5 mmol, the nanoparticles start having a more facet shape than spherical shape. Also, the size of particles in both cases was controlled by changing the temperature and time. Our data show that by changing the reaction temperature from 220 to 250 C, the average diameter of nanoparticles can be increased from 1-3 nm to 8-10 nm.

[1] Nemati, Z., (2018). J. Phys. Chem. C, 122 (4), 2367-2381.