Photoluminescence, Phosphorescent and Fluorescent Materials

FIGURE 12.47 Emission spectrum of a typical white phosphor. Ca,o(Po4)6(F, Cl)2 doped with and Mn +. 

Pure apatites, when they are suitably doped with traces of metal cations, will fnnction as phosphorescent materials (phosphors). Only -1% dopant is usually needed. Halophosphate phosphors were first discovered by McKeag and Ranby in 1942 [30a], 

Strontium pyrophosphate, Sr2P207, doped with Eu + -I- Mn +, will produce yellow fluorescence. Reported pyrophosphate phosphors include those of types 

Very recently, phosphonates of type Zni Mn lOjPPh) H2O) have been shown to emit a range of fluorescent colour, including reds and greens [36]. 

Polycrystalline hydroxy/fluor apatite solid solutions are proton conductors at 250-500°C, due to enhanced proton movement between the OH groups in the channel structure (Chapter 13.1). 

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