Europium, phosphors containing

Europium, isolation of materials containing samarium, ytterbium and, by means of sodium amalgam, 5 32, 33 phosphors containing strontium sulfide or selenide and, 3 21, 22... 

The main optical uses are in lasers, phosphors, and lenses. The single most important phosphors contain europium (III) in a yttrium host such as Y2O2S, which is used for the... 

Two simple examples will be given in order to illustrate the instrumentation and the primary data treatment. The discussion is focused on the technical problems and the interpretation of the results is left to a minimum. The first example deals with the resonance energy transfer (RET) from europium to an organic fluorophore. The distance between the donor and acceptor is kept constant by an oligonucleotide. RET is a very common technique in the case of lanthanides, and therefore the discussion is somewhat lengthy and detailed. The second example deals with a sample of upconversion phosphor containing yttrium, ytterbium and erbium. 

Bril and Wanmaker (149) examined the fluorescent properties of some europium-activated phosphors. In particular, they studied gadolinium oxide, gadolinium borate, gadolinium phosphate, lanthanum borate, and europium phosphate. The phosphors all show an emission spectrum characteristic of europium. From the excitation spectra one can deduce that, in the gadolinium containing host energy absorbed by the gadolinium, ions can be transferred to the europium ions. 

A systematic study of the luminescent characteristics of glasses containing rare earths was done in this laboratory (14—20). There has been considerable spectroscopic investigation involving europium activated phosphors for several reasons. The phosphors are of practical use in color television and more information about crystal levels can be obtained for even-electron systems than those with odd-electron systems. Reisfeld et al. (21—25) and Rice and DeShazer (26) have used the fluorescence of europium as an indicator of site S5nnmetry of rare earth ions in glasses. 

---