Preparation and luminescence properties of calcium bismuthborate red-lightglass doped with high concentration Eu³⁺

Eu³⁺-doped calcium bismuth borate glasses emitting red-light were prepared by a rapid melt quenching technique.The general physical properties of the glasses were tested, includingdensity, molar volume and refractive index.The excitation and emission spectra, the structure and thermal stability of the glasses were also analyzed.The results show that the density, refractive index, glass transition temperature (T_g)and thermal stability of glasses graduallyincrease with the increase of Eu³⁺ concentration.However, the molar volume decreases first and then increases with increasing the Eu³⁺ concentration.8%(means the mole fraction, same as below)of Eu₂O₃is the optimum doping concentration, and the maximum Eu₂O₃ concentration in glass forming area located at 9%.The glass structure exhibits a relatively low symmetry with an amorphous state, and the structure is mainly composed of BO₃ trigonal, BO₄ tetrahedron, BiO₃ trigonal and BiO₆ Octahedron.The fluorescent glasses, whichhave a high Eu³⁺ doping concentration, well matched degree with blue chip, excellent thermal stability, lower melting point and suitable refractive index, will be a good matrixapplied for glass-ceramic used in white LEDs.