Eu3+-doped bismuth silicate crystal structure and Mulliken charge analysis

The effects of Eu 3+ doping on the crystal structure and charge distribution of Bi 4 Si 3 O 12 (BSO) bisilicate, based on first principles and density functional theory (DFT), were calculated and analyzed using Materials Studio software. The effect of different proportions (1/12, 1/6 and 1/3) of Eu 3+ doping on BSO crystals was investigated using the virtual crystal approximation method. Through Mulliken charge analysis, it is found that a high proportion of Eu 3+ doping will destroy the symmetry of the crystal structure. With an increase of the Eu 3+ -doping ratio, the Eu—O bond length first increased and then decreased, showing the characteristics of covalent bonds, and the Eu—O bond length reached the minimum value when the Eu 3+ -doping ratio was increased to 1/3. With an increase in the Eu 3+ -doping ratio, the Bi—O bond length decreases sequentially and also reaches the minimum value when the Eu 3+ -doping ratio was increased to 1/3. This indicates that the covalence between the Eu—O and Bi—O atoms is enhanced when the doping ratio is 1/3 when BSO crystals are doped with Eu 3+ .