Size-tuneable synthesis of nickel nanoparticles

• Published in: Journal of nanoparticle research : an interdisciplinary forum for nanoscale science and technology 2012, Vol.14 (1), p.1-10, Article 670
• Main Authors: Donegan, Keith P., Godsell, Jeffrey F., Otway, David J., Morris, Michael A., Roy, Saibal, Holmes, Justin D.
• Format: Article
• Language: English
• Subjects: Alkylamines; Capping; Chains; Characterization and Evaluation of Materials; Chemistry and Materials Science; Inorganic Chemistry; Lasers; Ligands; Materials Science; Nanoparticles; Nanotechnology; Nickel; Optical Devices; Optics; Photonics; Physical Chemistry; Reaction time; Research Paper; Synthesis; Thermal decomposition; X-ray diffraction
• ISSN: 1388-0764; 1572-896X
• DOI: 10.1007/s11051-011-0670-y

A facile method is described for synthesising nickel nanoparticles via the thermal decomposition of an organometallic precursor in the presence of excess n -trioctylphosphine as a capping ligand. For the first time, alkylamines with different chain lengths were employed as size-limiting agents in this synthesis. A direct correlation is demonstrated between the size of the alkylamine ligands used and the mean diameter of the nickel nanoparticles obtained. The use of bulky oleylamine as a size-limiting agent over a reaction period of 30 min led to the growth of nickel nanoparticles with a mean diameter of 2.8 ± 0.9 nm. The employment of less bulky N,N -dimethylhexadecylamine groups led to the growth of nickel nanoparticles with a mean diameter of 4.4 ± 0.9 nm. By increasing the reaction time from 30 to 240 min, while employing oleylamine as the size-limiting agent, the mean diameter of the nickel nanoparticles was increased from 2.8 ± 0.9 to 5.1 ± 0.7 nm. Decreasing the amount of capping ligand present in the reaction system allowed further growth of the nickel nanoparticles to 17.8 ± 1.3 nm. The size, structure and morphology of the nanoparticles synthesised were characterised by transmission electron microscopy and powder X-ray diffraction; while magnetic measurements indicated that the particles were superparamagnetic in nature.