Broadband orange emission from Bi activated calcium fluorophosphate

• Bismuth doped Ca5(PO4)3F shows broadband orange emission.
• The abnormal reduction of Bi3+ to Bi2+ can be found in air.
• Ca5(PO4)3F lattice is necessary to favor the occurrence of Bi3+ to Bi2+ reduction.

Bi doped Ca5(PO4)3F phosphors were synthesized by the solid state reaction in air, and characterized by XRD and photoluminescence spectra. Including typical violet luminescence from Bi3+, broadband orange emission peaked at about 521 nm can be observed under UV light excitation. Emission data with the size available lattice sites suggest that there are two types of Bi, Bi3+ and Bi2+, in Ca5(PO4)3F lattice, and each locates on one of the two available Ca2+ sites. Bi2+ occupying Ca2+(1) sites is considered to be reduced from Bi3+ to Bi2+ and presents efficient orange emission.

A novel Bi doped Ca5(PO4)3F phosphor, which has two asymmetrical cationic (Ca2+) sites possible in this system, shows ultra-broadband orange emitting property of Bi2+.Figure optionsDownload as PowerPoint slide