Yttrium vanadate

Europium oxide is now widely used as a phospor activator and europium-activated yttrium vanadate is in commercial use as the red phosphor in color TV tubes. Europium-doped plastic has been used as a laser material. With the development of ion-exchange techniques and special processes, the cost of the metal has been greatly reduced in recent years. 

Some oxide-type minerals have been found to luminesce when irradiated. A simple example is ruby (aluminium oxide with chromium activator), which emits bright-red light. The phosphors are incorporated into colour television screens to emit the colours blue (silver-activated zinc sulphide), green (manganese-activated zinc orthosilicate), and red (europium-activated yttrium vanadate). 

TheNd + ion shows several absorption lines of different widths in crystals. One of the absorption lines of Nd + ion in yttrium vanadate (YVO4) peaks at 809 nm and presents a natural broadening at 2 K with a full width at half maximum of (A v)nat =18 GHz. Estimate (a) The natural broadeiung in the wavelengths units (nm) and (b) the lifetime of the excited state. 

Europium satisfies the needs of both red and blue phosphors. Typical materials used for the former are europium yttrium vanadate and yttrium oxysulphide doped with europium. Blue... 

An example of a coding phosphor is yttrium vanadate which is activated by trivalent rare earths. In another invention, that of Andersson (Ref 12), Ca silicate powdr of less than 6mm particle size is suggested for use as an adsorbing... 

Scott [48] has determined europium in yttrium phosphors. Yttrium vanadate (0.1 g) was fused with potassium carbonate (2g) in a platinum crucible. Yttrium oxide and yttrium oxysulphide can be dissolved directly in the same solvent as the above melt, 50% hydrochloric acid. Standard flame conditions for yttrium were used. 

So far neither work of phosphor films via the Pechini-type sol-gel proeess nor their direct patterning via soft lithography have been reported in literature. Yttrium vanadate (YVO4) has been shown to be a useful host lattice for rare earth ions to produce phosphors emitting a variety of coIors[7]. In this paper, we report a Pechini sol-gel synthesis of the nanocrystalline YV04 A (A=Eu, Sm, Er ) thin phosphor films and their... 

In the high-pressure mercury lamps for street lighting, yttrium vanadate doped with europium is deposited on the glass. This makes the light brilliant white and more natural. 

Various flux materials have been used for the preparation of europium-activated yttrium vanadate phosphor from vanadium and rare earth oxides. These include sodium nitrate and carbonate, and sodium and ammonium vanadates (Martin and Trond, 1967 Kauders, 1967 Yokota et al., 1970). A precipitation method in which the rare earths are precipitated in nitric acidic solution with NH4VO3 is also used in the preparation of phosphors (Martin and Trond, 1967). The precipitate is afterwards calcined to the flnal composition. 

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