Effects of Sr2+ content on microstructure and spectroscopic properties of Nd3+ doped Ca1-xSrxF2 transparent ceramics

CaF 2 -SrF 2 hosts with substitution disorder of Ca 2+ /Sr 2+ sites in the lattice provide lower local symmetry for RE 3+ ions compared with pure CaF 2 or SrF 2 hosts, thereby facilitating more efficient 4f → 4f transitions. Here we report a study of effects of Sr 2+ content on microstructure and spectroscopic properties of Nd 3+ doped Ca 1-x Sr x F 2 transparent ceramic. Phase and microstructure analyses show that when x is in the range of 0–0.25, Nd: Ca 1-x Sr x F 2 nanoparticles keep pure CaF 2 phase with their size, morphology and agglomeration degree mildly changed. Increasing x from 0 to 0.2 significantly improves the luminescence intensity, emission lifetime and emission cross-section of Nd: Ca 1-x Sr x F 2 , however, hardly affects the concentration quenching. The luminescence intensities and emission lifetimes of x = 0.2 and 0.25 samples are very close, probably indicating SrF 2 phase has already formed in x = 0.25 sample. Based on the spectroscopic properties, the optimal Sr 2+ content is found to be x = 0.2.