4.3.2.1 Arrays of Metal Nanocrystals
Gold organosols using alkane thiols as surfactants were first prepared by Schiffrin
and co-workers [109] by phase transferring gold ions and carrying out reduction
in the presence of thiols. Several workers have adopted this procedure to obtain
thiolized metal nanocrystals [110–113].
Whetten et al. [111] centrifuged the organosol and separated out fractions
containing nanocrystals of different mean sizes, to prepare well-ordered twodimensional arrays of size-selected Au nanocrystals. Harfenist et al. [59] found that
Ag nanocrystals prepared by using a cluster beam, were stable in air and formed
extended two-dimensional arrays. In Figure 4.10 is shown a TEM image of a twodimensional array of dodecanethiol covered Ag nanocrystals obtained by Fitzmaurice and coworkers [112]. The Ag nanocrystals were prepared following the
method of Schiffrin and co-workers [109]. Well ordered arrays of magic nuclearity
nanocrystals, Pd 561 and Pd 1415 , have been successfully obtained (see Figure 4.11)
after replacing their polymer coating by alkanethiols, following the phase transfer
method discussed previously [114]. Long chain fatty acids have also been used
Fig. 4.9. TEM image of a continuous stratum structure of
compressed LB film of Ag nanocrystals. One-dimensional
strings of Ag nanocrystals are clearly seen (reproduced with
permission from [107]).
4.3 Programmed Assemblies 63
Gold organosols using alkane thiols as surfactants were first prepared by Schiffrin
and co-workers [109] by phase transferring gold ions and carrying out reduction
in the presence of thiols. Several workers have adopted this procedure to obtain
thiolized metal nanocrystals [110–113].
Whetten et al. [111] centrifuged the organosol and separated out fractions
containing nanocrystals of different mean sizes, to prepare well-ordered twodimensional arrays of size-selected Au nanocrystals. Harfenist et al. [59] found that
Ag nanocrystals prepared by using a cluster beam, were stable in air and formed
extended two-dimensional arrays. In Figure 4.10 is shown a TEM image of a twodimensional array of dodecanethiol covered Ag nanocrystals obtained by Fitzmaurice and coworkers [112]. The Ag nanocrystals were prepared following the
method of Schiffrin and co-workers [109]. Well ordered arrays of magic nuclearity
nanocrystals, Pd 561 and Pd 1415 , have been successfully obtained (see Figure 4.11)
after replacing their polymer coating by alkanethiols, following the phase transfer
method discussed previously [114]. Long chain fatty acids have also been used
Fig. 4.9. TEM image of a continuous stratum structure of
compressed LB film of Ag nanocrystals. One-dimensional
strings of Ag nanocrystals are clearly seen (reproduced with
permission from [107]).
4.3 Programmed Assemblies 63