A Photoluminescence Study of Eu(3+), Tb(3+), Ce(3+) Emission in Doped Crystals of Strontium-Barium Fluoride Borate Solid Solution Ba(4−x)Sr(3+x)(BO(3))(4−y)F(2+3y) (BSBF)

The present study is aimed at unveiling the luminescence potential of Ba(4−x)Sr(3+x)(BO(3))(4−y)F(2+3y) (BSBF) crystals doped with Eu(3+), Tb(3+), and Ce(3+). Owing to the incongruent melting character of the phase, the NaF compound was used as a solvent for BSBF crystal growth. The structure of BSBF: Eu(3+) with Eu(2)O(3) concentration of about 0.7(3) wt% was solved in the non-centrosymmetric point group P6(3)mc. The presence of Eu(2)O(3) in BSBF: Eu(3+) leads to a shift of the absorption edge from 225 nm to 320 nm. The photoluminescence properties of the BSBF: Ce(3+), BSBF: Tb(3+), BSBF: Eu(3+), and BSBF: Eu(3+), Tb(3+), Ce(3+) crystals have been studied. The unusual feature of europium emission in BSBF is the intensively manifested (5)D(0)→(7)F(0) transition at about 574 nm, which is the strongest for BSBF: Eu(3+) at 370 nm excitation and for BSBF: Eu(3+), Tb(3+), Ce(3+) at 300 nm and 370 nm excitations. No evidence of Tb(3+)→Eu(3+) energy transfer was found for BSBF: Eu(3+), Tb(3+), Ce(3+). The PL spectra of BSBF: Eu(3+) at 77 and 300 K are similar with CIE chromaticity coordinates of (0.617; 0.378) at 300 nm excitation and (0.634; 0.359) at 395 nm excitation and low correlated color temperature which implies application prospects in the field of lightning. Due to the high intensity of (5)D(0)→(7)F(0) Eu(3+) transition at 370 nm excitation, the BSBF: Eu(3+) emission is yellow-shifted.