Inorganic materials phosphors

Luminescent inorganic materials (phosphors) have been in common use for several decades, those related to ZnS having been discovered in the mid-nineteenth century. Phosphors continue to be an important commodity, and there are efforts to improve the efficiency and colour of existing phosphors as well as to make new ones (Hill, 1983 Hagenmuller, 1983). Small quantities of impurities markedly affect the luminescence characteristics of phosphors for example one or two parts in 10 of copper dominates the luminescence of ZnS. 

Inorga.nicNIa.teria.ls. These include acids (sulfuric, nitric, hydrochloric, and phosphoric), bases (caustic soda, caustic potash, soda ash, sodium carbonate, ammonia, and lime), salts (sodium chloride, sodium nitrite, and sodium sulfide) and other substances such as chlorine, bromine, phosphoms chlorides, and sulfur chlorides. The important point is that there is a significant usage of at least one inorganic material in all processes, and the overall toimage used by, and therefore the cost to, the dye industry is high. 

Casein may be considered to be a conjugated protein, that is the protein is associated in nature with certain non-protein matter known as prosthetic groups. In the case of casein the prosthetic group is phosphoric acid. The protein molecule is also associated in some way with calcium. The presence of these inorganic materials has an important bearing on the processability and subsequent use of casein polymers. 

Phosphors are inorganic materials which convert incident radiant energy to visible light within a device. The device chosen can be a cathode-ray tube, i.e.- a television tube, or a fluorescent lamp. A phosphor consists of a matrix modified by an additive chosen so that it becomes optically active within the matrix, or compound. This is an example of a substitutional impurity in a lattice wherein the additive, usualty Ccdled an "activator", introduces a lattice defect that is optically active. However, the added impurity still follows all of the rules found for defects in a lattice, as shown by the following example. 

Principles and Characteristics Combustion analysis is used primarily to determine C, H, N, O, S, P, and halogens in a variety of organic and inorganic materials (gas, liquid or solid) at trace to per cent level, e.g. for the determination of organic-bound halogens in epoxy moulding resins, halogenated hydrocarbons, brominated resins, phosphorous in flame-retardant materials, etc. Sample quantities are dependent upon the concentration level of the analyte. A precise assay can usually be obtained with a few mg of material. Combustions are performed under controlled conditions, usually in the presence of catalysts. Oxidative combustions are most common. The element of interest is converted into a reaction product, which is then determined by techniques such as GC, IC, ion-selective electrode, titrime-try, or colorimetric measurement. Various combustion techniques are commonly used. 

Another need the organisms have in common with man is some inorganic materials. They need small quantities of nitrogen, phosphorous, and sulfur, plus trace quantities of iron, calcium, magnesium, manganese, zinc, boron, potassium, and cobalt.34 These are generally present in most municipal waters but may be absent from certain industrial waste streams. If this is so, they must be added. 

Tony Cheetham was a member of the Chemistry faculty at Oxford, 1974-1991, and has been at the University of California at Santa Barbara since 1991. He is Professor in both the Materials and Chemistry Departments at UCSB, and since 2004 has been the Director of the new International Center for Materials Research (ICMR). Cheetham s research interests lie in the area of functional inorganic materials and currently include hybrid framework materials, phosphors for solid state lighting, and inorganic nanoparticles. 

Phosphors are mostly solid inorganic materials consisting of a host lattice doped with impurities. The absorption of energy occurs through either the host lattice or the impurities and the emission invariably originates from the impurities. 

Numerous inorganic materials have been found or synthesized to luminesce. And thousands of them had been used as phosphors in illumination and display devices. Although some phosphors have demonstrated excellent optical properties to meet current requirements, the research on phosphors continues because the... 

The effect of the residual inorganic material of commercial carbons on their polarity and on the adsorption of certain contaminant in drinking water has been investigated ly Baker and co-woikers [354]. They used wood-based, phosphoric activated carbons with various contents of residual phosphates to study the effect on tte adsorption performance of both metallic species and organic compounds. The authors interestingly reported a direct relationship between the phosphate level on the carbon and the decrease in their adsorption capacities [354]. 

The in situ construction of the inorganic component within a cast polymer solution is not limited to metal oxides and in practice a range of other inorganic materials can be formed depending on the choice of precursor(s) incorporated in the polymer solution, and the nature of post-treatment following solvent removal. Roziere and Jones and co-workers have developed nano composite membranes in which zirconium phosphate is formed from zirconyl propionate introduced into a DMAc solution of sPEEK, by immersion of the cast film, after solvent removal, into phosphoric acid. This approach provides a robust synthetic route that can be generalised to other ionomers, and allows the amount of ZrP to be readily varied, even up to ca. 40-50 wt. %. 

Luminescence materials, also called phosphors, are composed of an inorganic material (host lattice) and an activator (a small amount of impure atoms are distributed in the host crystal). Either the host lattice or the activator absorbs energy to excite the luminescence. 

The major nontrivalent lanthanide ion that is encountered for its Imninescence property is Eu +. Europium(II) is mostly found in inorganic materials for its broad blue emission that comes from d f transitions. The most well-known material is BaMgAlioOi Eu + (BAM) tiiat is used in blue-emitting phosphors (Figure 1). 

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