Crystal Structure and Photoluminescence Evolution of La5(Si2+xB1–x)(O13–xNx):Ce3+ Solid Solution Phosphors

A series of iso-structural La 5 (Si 2+ x B 1– x )(O 13– x N x ):Ce 3+ phosphors with apatite structure have been prepared. A combination of powder X-ray diffraction and neutron scattering technique was employed to explore the crystal structural evolution and the rigid nature from oxy- to oxynitride-based apatites, and some local structures were also characterized by HRTEM and 29 Si NMR data, respectively. The new La 5 (Si 2+ x B 1– x )(O 13– x N x ):Ce 3+ solid solution phosphors gave continuously controlled emission from 421 nm [La 5 Si 2 BO 13:Ce 3+, end-member ( x = 0)] to 463 nm (La 5 Si 3 O 12 N:Ce 3+, end-member ( x = 1)). Substitution of B 3+ and O 2– by Si 4+ and N 3– in La 5 (Si 2+ x B 1– x )(O 13– x N x ):Ce 3+ phosphors produced more covalency into the crystal field environment around the Ce 3+ ions inducing the red-shifted emission, further improving the thermal stability of the oxynitride-based apatite phosphors. The proposed approach from oxy- to oxynitride based iso-structural phases could significantly contribute to future research in designing complex solid solution phosphors.