Synthesis of iron-based nanoparticles from ferrocene by femtosecond laser irradiation: Suppression of the particle growth in a mixture of water and hexane

[Display omitted] •Iron-based nanoparticles (mean diameter ca. 7 nm) are obtained without dispersants or centrifugation.•Size of nanoparticles is independent of reactant concentration and laser irradiation time.•Hexane microdroplets in water act as small reaction vessels. Iron-based nanoparticles show unique magnetic properties, and their syntheses from metal complex solution by pulsed lasers have been widely studied; however, the aggregation of nanoparticles is unavoidable in homogeneous solution. We report the production of water-dispersible iron-based nanoparticles in a mixture of water and ferrocene n-hexane solution by femtosecond laser irradiation without using any additive agents. The mean diameter of iron-based nanoparticles (ca. 7 nm) is independent on the concentration of ferrocene and laser irradiation time. We propose that hexane microdroplets dispersed in water act as reaction vessels and reduce the opportunity of aggregation of primary nanoparticles.