Thin film colors

A thin layer of dark green beryl had been grown by a hydrothermal technique over the surface of a pale beryl to imitate emerald. It has been suggested that such stones should be called synthetic emerald-beryl doublets (16). The abiHty to grow thin, but not thick, single-crystal diamond on the surface of natural diamond (17) leads to the possibiHty of growing such a thin film colored blue with boron this has been done experimentally (18). 

Electronic absorption spectra of thin films colored with copper phthalocyanines have also been recorded (see Figures 21—4 and 21-5). Compared to the solution spectra, solid state spectra have broader bands, and there is also a shift in the wavelength of maximum absorption. This is attributed to the phenomenon known as crystallochromy. In the solid state, electronic excitation takes place between bands of energy levels formed by the interaction (coupling) of the chromophores in the solid... 

Ito T., Matsuda H., Sakai K. Coating solution composition for forming glass gel thin film, color glass gel filta-, and display device nsing the same. USP5464566, 1995... 

Fig. 6 Transmittance spectra of Ti02 thin film colored in different electrolyte solutions...

Fig. 7 Transmittance spectra of TiO thin film colored in different concentrations of electrolyte solutions at 800 nm...

Any metal that can be anodized usually develops oxide coatings over each grain of a thickness depending on the composition and orientation of that grain. Transparent oxide films then show interference colors, which differentiate one grain from another. Picklesimer (1967) illustrates this technique for alloys of zirconium and niobium he also discusses older ways of developing thin film colors on metals both electrolytically and by heating. 

As a point of interest, it is possible to form very thin films or membranes in water, that is, to have the water-film-water system. Thus a solution of lipid can be stretched on an underwater wire frame and, on thinning, the film goes through a succession of interference colors and may end up as a black film of 60-90 A thickness [109]. The situation is reminiscent of soap films in air (see Section XIV-9) it also represents a potentially important modeling of biological membranes. A theoretical model has been discussed by Good [110]. 

Both the polymers are dark in color and exhibit semiconductivity and paramagnetism. The electric conductivity measurements are performed on peUets and on thin films in sandwich and surface ceUs. 

Phthalocyanines have been used to incorporate semiconductor properties in polymers (182) or to develop a thin-film transistor (183). Phthalocyanines and their derivatives can act as dyes in color photography (qv) (184) or electrophotography (185). Light-sensitive compositions for use on Hthographic plates are comprised in part of copper phthalocyanine blue (186). Dichlorosilicon phthalocyanine [19333-10-9] has been used in the... 

Although the pure metal has a silvery-white color, in the cast condition it may have a yellowish tinge caused by a thin film of protective oxide on the surface. When highly poHshed, it has high light reflectivity. It retains its brightness well during exposure, both outdoors and indoors. 

Clear-bright and blue-bright chromium conversion colors are thin films (qv) and may be obtained from both Cr(III) and Cr(VI) conversion baths. The perceived colors are actually the result of interference phenomena. Iridescent yellows, browns, bron2es, oHve drabs, and blacks are only obtained from hexavalent conversion baths, and the colors are Hsted in the order of increasing film thickness. Generally, the thicker the film, the better the corrosion protection (see Eilmdepositiontechniques). 

Gathodically Colored Inorganic Films. The generalized cathodic, monovalent ion-iasertion reaction for inorganic thin films is... 

Electronic conductivity of thin-film solid electrolytes. Besides having low electronic transference numbers, it is essential for thin films of the order of 1 jim that the magnitude of the electronic resistance is low in order to prevent self-discharge of the battery. For this reason, specific electronic resistances in the range of 1012-1014 Qcm are required for thin-film solid electrolytes. Often the color may be a valuable indication of the electronic conductivity. In this regard, solid electrolytes should preferably be transparent white [20]. 

Most LAB is sulfonated using thin-film S03 technology. In this process no spent acid is produced because the S03 reacts almost stoichiometrically with LAB. High-quality LAS slurry with low color and a low level of Na2S04 can be produced. Sulfonation of LAB yields predominantly the para isomer [14]. 

The particular colors that are observed at different angles will depend critically on the thickness of the thin film coating. Precision instrumentation is required to carefully control film thickness during production. The magnitude of the optical effect depends on the density of flakes in the ink, while the quality of the optical effect depends on the precise orientation or alignment of these flakes with respect to the paper surface. 

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