Nanocrystalline film

Mastai Y, Hodes G (1997) Size quantization in electrodeposited CdTe nanocrystalline films. 

H2Ga(N3)] volatile UHV-CVD 200-800 °C, silicon substrate gave wurtzite-phase GaN, nanocrystalline films with oxygen and carbon incorporation 291... 

This chapter deals mainly with quantum size effects in CD nanocrystalline films. However, another, quite separate property of such films is related to the large percentage of atoms located on the surface of the nanocrystals of these films, e.g. —50% for a crystal size of a few nm this is the effect of adsorption of molecular and ionic species on the nanocrystal surfaces. This aspect has been dealt with much less than has size quantization therefore, it constitutes only a very small part of this chapter, mainly Section 10.2.3, which discusses the effect of adsorbed water on CD CdSe films. Section 9.2.2.2 deals in somewhat more detail with this particular issue. 

Figure 2 A module of an photoelectrochemical solar cell based on a dye-sensitized TiOz nanocrystalline film.

Stepwise electron injection in the dye-sensitized nanocrystalline films of ZnO and Ti02 with novel coumarin dye... 

In Dr. M. Gratzel s plenary lecture at IPS-2000,103 he presented the following research topics to improve DSC. 1) Mastering the interfaces, electron transfer dynamics, control of dark current. 2) Charge transport in nanocrystalline films. 3) Panchromatic sensitizers, dye cocktail, quantum dot charge injection. 4) Light management, mixed metal oxide films, core-shell metal oxide films. 5) New... 

Fig. 10.28. Model of charge carrier separation and charge transport in a nanocrystalline film. The electrolyte has contact with the individual nanocrystallites. Illumination produces an electron-hole pair in one crystallite. The hole transfers to the electrolyte and the electron traverses several crystallites before reaching the substrate. Note that the photogenerated hole always has a short distance (about the radius of the particle) to pass before reaching the semiconductor/electrolyte interface wherever the electron-hole pair is created in the nanoporous film. The probability for the electron to recombine will, however, depend on the distance between the photoexcited particle and the tin-coated oxide back-contact. (Reprinted with permission from A. Hagfeldt and Michael Gratzel, Light-Induced Redox Reactions in Nanocrystalline Systems Chem. Rev. 95 49-68, copyright 1995, American Chemical Society.)...

Xagas APB, Hugot-Le Goff A, Spyrellis N, Loizos Z, Falaras P. Surface modification and photosensitisation of Ti02 nanocrystalline films with ascorbic acid. J Photochem Photo-biolA Chem 2000 132 115-20. 

Fig. 26 (a) Nanocrystalline film of Au formed al the toluene-water interface, (b) When dodecanethiol is added to the toluene layer, the film breaks up, forming an organosol of Au, (c) Au hydrosol obtained when mercaptoundecanoic acid is added to waler. TEM images of the ultra-thin nanocrystalline Au films obtained at the liquid-liquid interface after 24 h (d) 30 "C, (e) 45 °C, (0 60 °C and (g) 75 °C. The histograms of particle size distribution are shown. The scale bars correspond Lo 50 nm. A high-resolution image of an individual particle is shown at the center. Reprinted with permission from V. V. Agrawal, G. U. Kulkarni and C. N. R. Rao, J. Phys. Chem. B, 2005, 109, 7300. C J 2005, American Chemical Sociely. 

The Liquid-Liquid interface as a Medium To Generate Nanocrystalline Films of Inorganic... 

We shall illustrate the method of preparation of nanocrystalline films with two examples. To prepare nanocrystalline... 

FIGURE 1. Nanocrystalline films of (a) Au and (b) CdS formed at the toluene-water interface. 

Liquid-liquid Interface To Generate Nanocrystalline Films Rao and Kalyanikutty... 

Increasing the concentration of the metal precursor yields nanocrystalline films with a larger number of particles, but the size distribution is essentially unaffected. The thickness of the film also increases with the increase in the metal precursor concentration. The use of high concentrations of the reducing agent results in less uniform films with altered distributions in the nanoparticle diameter. A slight increase in the size of the Au nanoparticles was observed when the viscosity of the aqueous layer was increased by the addition of glycerol. 

Reactions at the interface carried out on a vibration-free table yielded nanocrystalline films with reduced roughness, comprising particles of smaller size. 

The Au films formed at the interface show interesting electrical transport properties that are dependent on the reaction temperature (see Figure 4).24 Four-probe electrical resistance measurements on the nanocrystalline films show a metal to insulator transition, metallic behavior being shown by the films formed at high temperatures (>45 °C). The films formed at lower temperatures (<45 °C) show insulating behavior. 

Till now, we have been examining the formation of uniform and robust nanocrystalline films of Au. The films, once... 

Ultrathin Nanocrystalline Films of Metals, Chalcogenides, and Oxides. J. Colloid Interface Sci. 2005, 289, 305-31B. 

C. N. R. Interfacial Rheology of an Ultrathin Nanocrystalline Film Formed at the Liquid/Liquid Interface. Langmuir 2007,23,3084-3087. 

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