CLASSICAL PHOSPHORS - A PANDORA BOX

The state-of-the-art of our fundamental understanding of a large numbe r of well-known luminescent ions used since long in phosphors is revie wed. These ions are WO42-, VO43-, Sb3+, Bi2+, Bi3+, Cu+, and Ce3+. The conclusion is that quantitative understanding is lacking and that in several cases even a qualitative explanation of the luminescence obser ved is not available.