Oleylamine nanoparticles

FIGURE 15.14 (See color insert following page 212.) Ink-jet printed gold oleylamine nanoparticle films printing onto paper at room temperature. 

Figure 7.7 Colloidal crystal formed from oleylamine-stabilized gold nanoparticles, Reproduced with permission from Harris etal.

In 2000, Sun and co-workers succeeded in synthesis of monodispersed Fe/Pt nanoparticles by the reduction of platinum acetylacetonate and decomposition of Fe(CO)5 in the presence of oleic acid and oleylamine stabilizers [18]. The Fe/Pt nanoparticle composition is readily controlled, and the size is tunable from 3 to 10 nm in diameter with a standard deviation of less than 5%. For practical use, we developed the novel symthetic method of FePt nanoparticles by the polyol reduction of platinum acetylacetonate (Pt(acac)2) and iron acetylacetonate (Fe(acac)3) in the presence of oleic acid and oleylamine stabilizers in di- -octylether [19,20]. The Fe contents in FePt nanoparticles can be tuned from 23 to 67atomic%, and the particle sizes are not significantly affected by the compositions, retaining to be 3.1 nm with a very narrow size distribution, as shown in Figure 6. 

Figure 15.1 Transmission electron microscopy images showing iridium nanoparticles prepared in four different capping ligands, (a) Oleic acid/oleylamine (b) TOAB ...

One assembly example is polyethylenamine (PEI)-mediated self-assembly of FePt nanoparticles [56]. PEI is an all -NH-based polymer that can replace oleate/oleylamine molecules around FePt nanoparticles and attach to hydrophilic glass or silicon oxide surface through ionic interactions [52], A PEI/FePt assembly is readily fabricated by dipping the substrate alternately into PEI solution and FePt nanoparticle dispersion. Figure 10 shows the assembly process and TEM images of the 4 nm Fes8Pt42 nanoparticle self-assemblies on silicon oxide surfaces. Characterizations of the layered structures with X-ray reflectivity and AFM indicate that PEI-mediated FePt assemblies have controlled thickness and the surfaces of the assemblies are smooth with root mean square roughness less than 2 nm. 

Peng er a/.6 "71 have proposed the use of greener Cd sources such as cadmium oxide, carbonate and acetate instead of the dimethylcadmium. These workers suggest that the size distribution of the nanocrystals is improved by the use of hexadecylamine, a long-chain phosphonic acid or a carboxylic acid. The method can be extended to prepare CdS nanoparticles by the use of tri-n-octylphosphine sulfide (TOP-S) and hexyl or telradecyl phosphonic acid in mixture with TOPO-TOP. Hyeon and coworkers71 have prepared nanocrystals of several metal sulfides such as CdS, ZnS, PbS, and MnS with different shapes and sizes by the thermolysis of metal-oleylamine complexes in the presence of S and oleylamine (Fig. 7). 

They have the face-centered tetragonal structure and thus obtain a unique property of recording advantage of large coercivity when in room temperature, no matter how small the particles are. Prepared by joint thermolysis in the presence of oleic acid and oleylamine, FE—Pt nanoparticles have a narrow size distribution. After further heating, a protective film is formed on the surface of alloys, which remain about the same size. 

A facile two phase route to PbS nanoparticles with narrow size distribution was developed.In the first phase, lead oxide and myristic acid were reacted at high temperature to form lead myristate. The resultant product was then added together with oleylamine and toluene in a flask at 80-90 °C to form an optically clear solution. The solution was transferred to stainless steel autoclave where a thiourea solution was added. Reactions were carried out at various temperatures followed by precipitation with methanol and separation by centrifugation. The spherical particles were approximately 4.0 nm in size and displayed narrow emission. The work function of PbS nanoparticles as a function of size and type of capping ligand was measured using gas phase core level... 

A chemical preparation route was also used to prepare Pt on Ag nanoparticles, where silver trifluoroacetate was mixed with oleylamine in isoamyl ether to synthesize Ag nanoparticles which were isolated, washed, then further reacted with... 

Oleic acid and oleylamine are used as the capping agents to control the growth of metal and metal alloy nanoparticles [16]. Cube, octahedral, prism, tripod, octapod, rod, and various other shapes have been obtained by using these two surfactants [16c]. Pt cubes, tripods, and multipods were made by using alternative surfactants, such as ada-mantinecarboxylic acid (ACA) and hexadecylamine (HDA) [17]. 

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