Abstract

By implementing transmission electron microscope (TEM) image processing, effects of a reducing agent and surfactant concentrations on the reactions between Pt(acac) <inf>2</inf> and alternative Fe(β-diketonate) <inf>3</inf>, i.e., Fe(tmhd) <inf>3</inf> and Fe(hfac) <inf>3</inf>, can be determined. The oleic acid and oleylamine of 0.5 mmol give rise to the FePt-based nanoparticles as small as 3 nm. Larger particles up to 5 nm in diameter with better self-assembled patterns are obtained by increasing each surfactant to 5 mmol. With such excessive surfactants in the synthesis, the reducing agent such as 1,2-hexadecanediol may not be required since it does not significantly influence the particle size and assembly. Moreover, it accelerates the reduction of Pt(acac) <inf>2</inf>, resulting in larger size distribution. This work demonstrates that image processing allows the size analysis from statistically sufficient number of nanoparticles. This intensity-based analysis is, however, susceptible to the error arising from a low contrast between the nanoparticle and the background. The magnification of TEM images should therefore be optimized to minimize systematic errors.