Cerium is more abundant and cheaper than the other rare earth elements.The Ce

3+

luminescence is due to a f-d transition with a broad emission bands.Its decay time of the fluorescence is very short

usually in the range of 30-100 ns.The phosphors with Ce

3+

ion find applications in cathodolu-minescence and photoluminescence

and they are scintillator materials.So people havebeen interested in Ce

3+

luminescence.The Ce

3+

luminescence varies strongly with host lattice and local surroundings.The energy transfer and sensitization had been studied between Ce

3+

and Ln

3+

ions in several materials.