Nanoparticle films superlattices

Schmitt J, Decher G, Dtessick WJ, Brandow SL, Geer RE, Shashidhar R, Calvert JM. Metal nanoparticle/polymer superlattice films fabrication and control of layer structure. Adv Mater 1997 9 61-65. 

Nanoparticle controllable assembly refers to the assembly of nanoparticles into controlled nanostructures (wires, rods, belts, rings, tubes, thin films, superlattices, and sophisticated 3D nanostructures) via interactions like electrostatic interaction, covalent interaction, metal-Ugand interaction, etc. 

Generation of nanoparticles under Langmuir monolayers and within LB films arose from earlier efforts to form nanoparticles within reverse micelles, microemulsions, and vesicles [89]. Semiconductor nanoparticles formed in surfactant media have been explored as photocatalytic systems [90]. One motivation for placing nanoparticles within the organic matrix of a LB film is to construct a superlattice of nanoparticles such that the optical properties of the nanoparticles associated with quantum confinement are preserved. If mono-layers of capped nanoparticles are transferred, a nanoparticle superlattice can be con-... 

Figure 15.28 TEM images of (a) Au nanoparticle arrays in mesoporous silica film (b) superlattice of extracted Au nanoparticles stabilized with 1-dodecanethiol.

Switzer, J.A. (1998) Electrodeposition of superlattices and nanocomposites, in Nanoparticles and Nanostructured Films (ed. J.H. Fendler), Wiley-VCH Verlag GmbH, Weinheim, pp. 53-70. 

Beverly et al. [93] studied the temperature-dependent DC transport measurements on monolayers of self-assembled dodecanethiol-coated 7 nm silver nanoparticles as a function of particle size distribution-induced disorder. The superlattices disorder was adjusted by a stepwise variation of the particle size distribution. In the electrical transport measurements, six different monolayers of 7 nm silver nanoparticles, in which the size distribution was varied from 6.6% to 13.8%, were investigated at 300-10 K. Above 200 K, all films exhibited metallic conductivity, and below 200 K activated transport. However, between 30 and 100 K a second transition (Tcross) was observed that was based on the crossover from the simply activated transport to a... 

In the previous sections, with a few exceptions (Section 6.8), mostly bulk properties are being discussed. In the case of superlattices, thin films, exposed surfaces and nanoparticles, the bulk properties are often considerably modified. For instance, surface composition is invariably different from the bulk as are the coordination polyhedra of cations. In addition, distortions such as octahedral tilting may be blocked in the bulk but become allowed at surfaces, leading to significant changes in surface strain. 

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