Nanoparticles solution

Scheme 2. Encapsulation of size- and shape-controlled Pt nanoparticles under neutral hydrothermal synthesis conditions of SBA-15. Silica templating block copolymers and silica precursors were added to PVP-protected Pt nanoparticle solutions and subjected to the standard SBA-15 silica synthesis conditions. Neutral, rather than acidic pH conditions were employed to prevent particle aggregation and amorphous silica formation [16j. (Reprinted from Ref. [16], 2006, with permission from American Chemical Society.)...

Fig. 13 UV-vis spectrum of ODA-AOT-capped gold nanoparticle solutions with decreasing concentrations of ODA (a) 0.5, (b) 0.1, and (c) 0.05 M. Inset shows the corresponding gold nanoparticle solutions. (Adapted from [66])...

As an example of the latter technique, Volkman et al. demonstrated the feasibility of using spin-cast zinc oxide nanoparticles encapsulated in 1-dodecanethiol to fabricate a functional transistor.44 The zinc oxide was deposited on a thermally grown silicon dioxide layer on a conventional silicon wafer, with thermally evaporated gold source and drain electrodes. As reported, the process requires very small particles (3nm or less) and a 400 °C forming gas anneal. A similar approach was also reported by Petrat, demonstrating n-channel thin-film transistor operation using a nanoparticle solution of zinc oxide dispersed onto a thermally grown silicon dioxide layer on a conventional... 

Bieri, N. Chung, J. Haferl, S. Poulikakos, D. Grigoropoulos, C. 2003. Microstructuring by printing and laser curing of nanoparticle solutions. Appl. Phys. Lett. 82 3529-3531. 

Brown, K.R., Walter, D.G., and Natan, M.J., Seeding of colloidal Au nanoparticles solutions.2. Improved control of particle size and shape, Chem. Mater., 12, 306, 2000. 

Modification typically takes advantage of electrostatic interactions between charges on the surface of the macromolecules and the polar headgroups of surfactants. We reasoned that the host-guest interactions at the nanoparticle-solution interface investigated in this work could be used for similar purposes. (From Liu et ah, 2001)... 

The assembly of monolayers of alkylbromide-functionalized Co nanoparticles onto amino-terminated silicon surfaces through direct nucleophilic substitution was reported by Kim et al.17 The nanoparticle density on the surface can be controlled by changing the immersion time of the silicon surface in the nanoparticle solution. Directed assembly of nanoparticles was observed on a chemically patterned surface. 

Figure 13.11 The patterning of nanoparticle crystals by combination of photolithography and surface wettability.75 A concentrated nanoparticle solution slowly evaporated in the gaps between the patterned substrate and a glass substrate. When the structure was peeled off, patterned nanoparticle crystals on both surfaces were formed.

Figure 13.12 The preparation of spherically shaped nanoparticle crystals. A chemically patterned SAM with attached droplets of a SiC>2 nanoparticle solution was immersed in decalin. The interfacing between two solutions and shrinkage of the particle droplets resulted in rearrangement of the nanopaiticles to form close-packed spherical particle assemblies.

Figure 4.2 (A) Series of normalized extinction spectra of chemically synthesized colloidal Ag nanoparticle solution showing the tuning of the plasmon resonance across the visible region. (B) Images of colloidal nanoparticle solutions. The differences in color are due to variations in the size and shape of the nanoparticles within each solution.

Analysis of SEM images of Ag NPs deposited on a surface (data not shown) yielded the estimate of the Ag NP diameter of c sem = 57 31 nm. Measurements of optical extinction spectra of Ag nanoparticle solution and their comparison with the predictions of the optical scattering theory [5] produced a value of dahs = 55 nm. These data are consistent with the ones previously reported [6] for Ag NPs produced by the same method. 

Even larger probes of bent and kinked DNA are 40 A photoluminescent mineral colloidal particles of CdS [247-253]. These nanoparticles are approximately the size of proteins and can be made in a variety of sizes ( 20-100 A) and decorated with a variety of surface groups [267-279]. The emission spectrum of a nanoparticle solution depends on particle size and surface group synthetic procedures for CdS and other semiconductor nanoparticles have been developed so that the emission can be tuned throughout the visible spectrum and into the near infrared [267-279]. Moreover, the photoluminescence of CdS is sensitive to adsorbates [280-289], and thus these nanomaterials can function as luminescent chemical sensors. 

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