Nanoparticles polycrystalline films

Sintering Metal and Semiconductor Nanoparticles into Continuous Polycrystalline Films... 

Recently, R nanoparticle layers [e.g., Y Bour et al. (2001), Gd Aruna et al. (2004)] have also been utilized as the active layer in the switchable mirrors. In these New generation switchable mirrors , in addition to the size dependent switchable properties, utilization of nanoparticle layers showed that it was possible to tune the band gap of the trihydride state by varying the nanoparticle size (Aruna et al., 2004) and sense very low concentrations of hydrogen (Bour et al., 2001). In a recent study, the use of Pd nanoparticle over layer to enhance the hydrogen induced switching properties of the Gd polycrystalline films has been reported (Aruna et al., 2005c). The studies are discussed in detail in section 4. 

Fig. 157. X-ray diflxactogranis of as-deposited Gd (a) nanoparticle and (b) polycrystalline films capped by a Pd laya-. The thick vertical lines represent the calculated (MZ) values corresponding to the f.c.c. structure and the thin lines represent the Qikl) values corresponding to the h.c.p. structure of Gd. The XRD peak at 29 = 40.1° corresponds to the (111) plane of f.c.c. structure of Pd. The inset shows the TEM micrc raph of Gd film nanoparticle film with an average particle size of 8 nm (Aruna et al., 2004).

The hydrogen-induced optical and electrical switching behavior were studied in Gd nanoparticle and polycrystalline films (30 nm) capped with a Pd over layer (10 nm) (Aruna et al., 2004). In comparison with the polycrystalline Gd films, Gd nanoparticle films were observed to show improved optical and electrical switching behavior. First, the optical trans-... 

A detailed X-ray photoelectron spectroscopy study was carried out to understand the effect of nanoparticle nature on the Pd-Gd interface. In case of Gd polycrystalline films, Pd 4d peak was observed to become narrow (FWHM of the Pd 4d peak decreases from 4.78 eV to... 

Fig. 163. (i) Valance band spectra of Pd capped Gd nanoparticle (a) and (b) polycrystalline films at different sputtering times. Intensity of Gd 4f peak increases and that of Pd 4d decreases on going from Pd to Gd at Pd-Gd interface, (ii) Change in FWHM and binding energy of Pd 4d electrons as a function of sputtering time for nanoparticle (solid symbols) and polycrystalline (hollow symbols) films (Aruna et al., 2004). 

The mode of 2,6-dimethylphenyl isocyanide (DMPI) adsorption on Pt electrodes [43] has been studied using potential-dependent SERS. The Pt electrodes were obtained by depositing Pt nanoparticles ( 17nm) on a polycrystalline Pt film. Three bands appear, at 2166, 2124 and 1997cm" , when DMPI is adsorbed on the... 

Specifically for the preparation of zeolite films, zeolite nanoparticles could be used directly to form zeolite films by self-assembly. They could also be combined nicely with the seeded growth and vapor phase transport method to produce high quality polycrystalline zeolite films. There is clear evidence that small zeolite nanoparticles are preferred for producing compact continuous films. 

A film of Ag nanoparticles embedded in a polycrystalline Ce,o matrix was grown by codeposition under high vacuum. The Raman spectrum shift to lower frequency observed... 

Fig. 15.25 Pathways for future electrocatalyst development for automotive PEMFCs. (a) Thick films or bulk single crystal and polycrystalline catalysts that are ideal for fundamental studies on surface structure and mechanisms these materials need to be modified into (c) and (d) to be applicable to fuel cells, (b) Typical commercial nanoparticles (2-4 nm) on a high-surface-area carbon support used in fuel cells at this time (c) Thin continuous films of catalyst on a support such as carbon nanotubes that may provide a physical porous structure for mass transport in a fuel cell (d) Core-shell catalysts where only the shell eonsists of precious metals and are supported on a typical high-surface-area support [72, 77, 89]...

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