Synthesis, characterization of new Bi3+ containing apatites: Formation of red emitting phosphors by Eu3+ incorporation

Abstract Single phase phosphosilicates, Ca 7 Bi 3 (PO 4 ) 5 (SiO 4 )O 2 , Ca 6 Bi 4 (PO 4 ) 3 (SiO 4 ) 3 OF and Ca 8 Bi 2 (PO 4 ) 4 (SiO 4 ) 2 F 2 have been synthesized and characterized by powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy and Raman spectroscopy. The charge balanced stoichiometries in the present investigation derived out of cationic and anionic variations lead to the formation of apatites with high Bi 3+ content. PXRD Le Bail refinements were carried out in space group P 6 3 (No. 173) instead of P 6 3 /m . Eu 3+ substitution has been carried out to append luminescence property to the lattice. Investigation of Eu 3+ luminescence revealed emission features consistent with its presence in the lower symmetry (6 c ) and the higher symmetry (2 b ) sites. The CIE coordinates of the Eu 3+ doped (5 mol%) apatite samples resulted in red emission.