Nanoparticles and Thin Films

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. 

Mechanical stress will deform a solid and the question arises as to whether it is possible to switch polarisation in a ferroelectric by the application of stress. The 

Principles and Applications of Ferrvelectrics and Related Materials, Oxford Classics, Oxford University Press, Oxford (2001). 

For an introduction to dielectric properties and the relationship with crystal structures see  

Tilley, Understanding Solids, 2nd edition, John Wiley Sons, Ltd, Chichester (2013), particularly Chapter 11. 

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The covalent nature of III-V materials causes problems for preparation of highly crystalline nanoparticles and thin films. A single-molecular precursor approach was employed to produce III-V nanoparticles of InP and GaP using the indium/gallium diorganophosphide compounds... 

In recent years, metal nanoparticles and thin films supported on oxides have become fundamental components of many devices as their small dimensions present structures with new chemical and physical properties, often enhancing the reactivity of these surfaces relative to their bulk counterparts. Numerous theoretical and experimental studies show that the metal particle size and shape as well as direct adsorbate interactions with the oxide support can each play a key role in enhancing the reactivity of these surfaces. Further investigations imply that the support material may... 

Pt(S2CNMe(Hex))2] and [Pd(S2CNMe(Hex))2] have been synthesized and used as precursors to grow the first TOPO-capped PtS and PdS nanoparticles and thin films of PtS and PdS by the metallo-organic chemical vapor deposition (MOCVD) method [204]. Platinum and palladium chalcogenides find applications in catalysis [205-210] and materials science [211,212]. The synthesis of thiocarbamato complexes of platinum and palladium from reaction of an aqueous solution of ammonium dithiocarbamate with the platinum or palladium salt has been reported by Nakamoto et al. [213]. However... 

Metallic Iron, Iron Nanoparticles, and Thin Films... 

Y. Y. Wang, K. F. Cai, X. Yao, Facile Synthesis of PbTe Nanoparticles and Thin Films in Alkaline Aqueous Solution at Room Temperature. Journal of Solid State Chemistry 2009,182,3383-3386. 

The main results of experimental studies of size effects in nanoferroics are presented in second chapter. In particular, we collect the extensive experimental data about size effects in nanoparticles and thin films of ferroelectrics, ferroelastics and magnetically ordered ferroics. The data have been collected for different nanoparticles geometries like spherical and cylindrical as well as for nanowires, nanotubes and nanopills. As for nanosizes the local properties play a decisive role, we pay attention to the results of electron spin resonant measurements, which are sensitive to the local properties. To obtain the reliable information about the physical properties of the entire nanostructure, the above local methods should be augmented by other experimental techniques like dielectric, magnetic and optical methods. We hope that our collection of available experimental data will give the idea about both local and average static and dynamic properties of nanostructures. 

Sol-gel processing has a long track record in producing useful materials for magnetic applications, in particular, magnetic nanoparticles and thin films. 

The nature of the interactions with the surface, however, does have a significant impact on the change of the polymer dynamics on confinement. For both the nanoparticle and thin film states of confinement, it has been shown that dynamics of the polymer are fadlitated or speed up near a surface with repulsive or weak interactions, whereas the dynamics slow down near a strongly interacting This has... 

Similar polymer/Au nanoparticle multilayer thin films were made by Wu et al. in a study of pH-sensitive dissociation behavior of poly (3-thiophene acetic acid) (PTA A) and PAA in a LbL film (of 8 bilayers).50 Unlike the pure polymer LbL film, the Au nanoparticles-containing LbL films were difficult to be released from the substrate by varying the pH. It was suggested that the gold particles act as a cross-linker in between the multilayers, thus further enhancing the stability of the LbL films. 

Lian and coworkers reported two routes to prepare Au nanoparticle multilayer thin films using two types of Au nanoparticles, respectively surface-modified with carboxylic and pyridine groups. In the first route carboxyhc-functionalized Au particles and P4VP were deposited, whereas in the second route pyridine-fimctionalized Au particles and PAA were used. Similarly, CdSe nanoparticles with acrylic acid surface groups were deposited alternately with P4VP [259,260]. 

A different approach to the stability of hydride nanoparticles is bottom-up, using computational techniques to construct equilibrium (lowest energy) configurations for the clusters, nanoparticles or thin films of the metal and corresponding hydride, and evaluate the difference in stability between the two as a function of particle size. Although the possibilities are rapidly increasing, these calculations are still limited to small cluster sizes due to computational restraints. As a relevant example we vhll only briefiy discuss various types of calculations for the case of the ionic hydrides MgH2 and NaH. 

Colloidal dispersions and thin films containing PEPC, PVC and Ag-Au nanoparticles were prepared and investigated by transmission electron microscopy (TEM) and UV-Vis-IR spectroscopy. Current-voltage characteristics... 

We show by X-ray diffraction in the Bragg-Brentano geometry that the atomic stmcture of lead sulfide nanoparticles in thin films prepared by wet chemical method is different from the B stmcture, which is the equilibrium phase for bulk single-crystalline PbS. The atomic structure of nanoparticles can be desaibed by the cubic space group Fm-3m with both tetrahedral and octahedral coordinations for sulfur atoms. 

Burnside S. D., Shklover V., Barbe C., Comte P., Arendse F. and Brooks K. (1998), Self-organization of Ti02 nanoparticles in thin films , Chem. of Materials 10, 2419-2425. 

Diblock copolymer poly(methyl methacrylate)-W0c -poly(2-hydroxyethyl methacrylate) PMMA- -PHEMA was used as the template for the self-assembly of palladium nanoparticles.98 Thin films of the metal-free block copolymer were obtained by dip coating from different solvents. The copolymer existed in the ordinary form and inverted micelles when it was dissolved in 1,4-dioxane and methanol, respectively. This was attributed to the hydrophilic properties of the PHEMA block. 2-Methoxyethanol, which is a common solvent to both blocks, was also used in the coating. Films obtained from 1,4-dioxane and methanol solutions showed the formation of spherical domains that were arranged in a 2-D hexagonal lattice, while the film obtained from 2-methoxyethanol showed a stripe pattern. Their AFM topography images are shown in Figure 5.19. The block copolymer thin films were then exposed to... 

Sohn BH, Seo BH (2001) Fabrication of the multilayered nanostructure of alternating polymers and gold nanoparticles with thin films of self-assembling diblock copolymers. Chem Mater 13(5) 1752-1757... 

PHOTOCHEMISTRY AND PHOTOELECTROCHEMISTRY OF QUANTIZED MATTER PROPERTIES OF SEMICONDUCTOR NANOPARTICLES IN SOLUTION AND THIN-FILM ELECTRODES... 

Quantized Matter, Photochemistry and Photoelectrochemistry of Properties of Semiconductor Nanoparticles in Solution and Thin-Film Electrodes... 

A novel method of a photocatalytic lithography based on a photogeneration of Pd nanoparticles in thin films of Pd2+-doped nanostructured titania followed by an electroless nickel plating is proposed. The possibility of a generation of both negative and positive metal patterns employing TiC>2 Pd2+ photolayers is discussed in terms of a dispersity of a photoproduced Pd nanophase and its catalytic activity towards an eletroless nickel deposition. 

PREPARATION AND SOME FEATURES OF COLLOIDAL DISPERSIONS AND THIN FILMS CONTAINING Ag-Au NANOPARTICLES... 

The colloidal dispersions and thin films containing poly-iV-(epoxypropyl)-carbazole (PEPC) and Ag-Au nanoparticles were prepared and investigated by TEM and UV-vis spectroscopy. The interaction between poly-iV-(epoxypropyl)-carbazole and Ag-Au nanoparticles were studied by IR-spectroscopy. It was shown that interaction of nanoparticles and polymer functional groups is determined by the conditions of a polymer addition. 

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