Chemical bond parameters, bond energy and the local crystal sites of Eu 3+ in Ca 5 (BO 3 ) 3 F:1% Eu 3+ phosphor.

The local crystal sites occupied by Eu 3+ in Ca 5 (BO 3 ) 3 F:1% Eu 3+ phosphor were investigated experimentally and theoretically. Ca 5 (BO 3 ) 3 F:1% Eu 3+ was synthesized by high-temperature solid-state method in air. The crystal structure and optical properties of the phosphor were studied by X-ray powder diffraction and photoluminescence, respectively. Two different O 2- → Eu 3+ CT broad bands with the peaks at 266 and 283 nm in Ca 5 (BO 3 ) 3 F:1% Eu 3+ were detected, indicating the Eu 3+ sites occupied Ca2 and Ca1, respectively. The different sharp f-f emission spectra under the excitation of 283 and 266 nm proved that there are two different local lattice environments around Eu 3+ existing in Ca 5 (BO 3 ) 3 F:1% Eu 3+ . Environmental factor h e , the standard deviation of environmental factor (EFSD) and the bond energy were used to illustrate and explain the site occupancy mechanism of Eu 3+ into the host lattice. By comparing the intensity ratios of 5 D 0 → 7 F 2 transition to the 5 D 0 → 7 F 1 transition, I ( 5 D 0 / 7 F 2 )/ I ( 5 D 0 / 7 F 1 ) of Eu 3+ at Ca2 (7.381) was found to be 2.5 times stronger than that of Eu 3+ at Ca1 site (2.933). was calculated to analyze the I ( 5 D 0 / 7 F 2 )/ I ( 5 D 0 / 7 F 1 ) value. On the basis of the bond valence model, a bond-energy method was used to study the occupancy of the Eu ion, which indicated that the preferential sites of Eu ion occupancy in the Ca 5 (BO 3 ) 3 F are the Ca2 and Ca1 sites. All three theoretical calculation results are consistent with each other.