Transparent metal oxide

The dominant class of nacreous pigments is based on platelets of natural mica coated with thin films of transparent metal oxides (see Fig. 73). Mica minerals are sheet silicates (laminar). Nacreous pigments are usually based on transparent muscovite [9941-63-5] but some are based on natural or synthetic phlogopite [110710-26-4]. Although muscovite occurs worldwide, few deposits are suitable for pigments it is biologically inert and approved for use as a filler and colorant [5.220], [5.221],... 

The actual metal surface that takes part in the bonding is illustrated in Fig. 16.1. Adhesives recommended for metal bonding are in reality used for metal-oxide bonding. They must be compatible with the firmly bound layer of water attached to surface metal-oxide crystals. Even materials such as stainless steel and nickel or chromium are coated with transparent metal oxides that tenaciously bind at least one layer of water. 

Rothenberger G., Fitzmaurice D. and Gratzel M. (1992), Optical electrochemistry. 3. Spectroscopy of conduction-band electrons in transparent metal-oxide semi-... 

G. Rothenberger, D. Fitzmaurice, M. Gratzel, Optical electrochemistry spectroscopy of conduction-band electrons in transparent metal-oxide semiconductor-films - optical determination of the flat-band potential of colloidal titanium-dioxide Aims, J. Phys. Chem. 1992, 96(14), 5983-5986. 

Dye sensitized solar cells built without any transparent metal oxide electrodes (ITO or FTO) were presented recently by Kashiwa et The layout of the device is shown in Figure 11. To fabricate such device, titanium dioxide paste was coated directly on a glass substrate. On the top of Ti02 layer, tetrapode-shaped nanocrystals of zinc oxide were deposited by electrospray technique. A layer of metal titanium was sputtered on the top. Following etching of the zinc oxide template produced pores in the titanium layer. 

Thin films of transparent metal oxide semiconductor (e.g., indium tin oxide and fluorine doped tin oxide) deposited on a transparent medium are finding increasing application because thick films can be used due to the optical transparency of metal oxides in the visible region of the spectrum and there are fewer problems with resistance than for thin metal films. The drawback to these materials is that they do not transmit ultra violet... 

The dominant class of pearlescent pigments is based on platelets of natural mica coated with thin films of transparent metal oxides The mica substrate acts as... 

The word glass commonly means the transparent substance obtained when white sand is fused with metal oxides or carbonates to give a mixture of silicates. Ordinary or soda-glass has the approximate composition NajO. CaO. 6Si02. (This is the composition obtained by analysis it does not represent the compounds present.) If sodium is replaced by potassium the melting point is... 

Transmission Fourier Transform Infrared Spectroscopy. The most straightforward method for the acquisition of in spectra of surface layers is standard transmission spectroscopy (35,36). This approach can only be used for samples which are partially in transparent or which can be diluted with an in transparent medium such as KBr and pressed into a transmissive pellet. The extent to which the in spectral region (typically ca 600 4000 cm ) is available for study depends on the in absorption characteristics of the soHd support material. Transmission ftir spectroscopy is most often used to study surface species on metal oxides. These soHds leave reasonably large spectral windows within which the spectral behavior of the surface species can be viewed. 

In choosing a SAM system for surface engineering, there are several options. Silane monolayers on hydroxylated surfaces are an option where transparent or nonconductive systems are needed. However, trichlorosilane compounds are moisture-sensitive and polymeri2e in solution. The resulting polymers contaminate the monolayer surface, which occasionally has to be cleaned mechanically. CarboxyUc acids adsorb on metal oxide, eg, AI2O2, AgO through acid—base interactions. These are not specific therefore, it would be impossible to adsorb a carboxyUc acid selectively in the presence of, for example, a terminal phosphonic acid group. In many studies SAMs of thiolates on Au(lll) are the system of choice. 

Special forms of highly transparent iron oxides are made for use in durable metallized polychromatic finishes. These products are more brown than yellow however, when used in metallized finishes, they impart a golden color. This type of iron oxide tends to be more reactive than the opaque yellows. 

Accelerated sulphur systems also require the use of an activator comprising a metal oxide, usually zinc oxide, and a fatty acid, commonly stearic acid. For some purposes, for example where a high degree of transparency is required, the activator may be a fatty acid salt such as zinc stearate. Thus a basic curing system has four components sulphur vulcanising agent, accelerator (sometimes combinations of accelerators), metal oxide and fatty acid. In addition, in order to improve the resistance to scorching, a prevulcanisation inhibitor such as A -cyclohexylthiophthalimide may be incorporated without adverse effects on either cure rate or physical properties. 

---