 It is a <unk> in some types of glass in lasers and other <unk> devices . Europium oxide ( Eu2O3 ) is widely used as a red phosphor in television sets and fluorescent lamps , and as an <unk> for yttrium @-@ based phosphors . Color TV screens contain between 0 @.@ 5 and 1 g of europium oxide . Whereas trivalent europium gives red phosphors , the luminescence of divalent europium depends on the host lattice , but tends to be on the blue side . The two classes of europium @-@ based phosphor ( red and blue ) , combined with the yellow / green <unk> phosphors give " white " light , the color temperature of which can be varied by altering the proportion or specific composition of the individual phosphors . This phosphor system is typically encountered in helical fluorescent light bulbs . <unk> the same three classes is one way to make <unk> systems in TV and computer screens . Europium is also used in the manufacture of fluorescent glass . One of the more common persistent after @-@ glow phosphors besides copper @-@ doped zinc sulfide is europium @-@ doped <unk> <unk> . Europium fluorescence is used to <unk> <unk> interactions in drug @-@ discovery screens . It is also used in the anti @-@ counterfeiting phosphors in euro <unk> . 
