Effect of yttrium on electron-phonon coupling strength of 5d state of Ce3+ ion in LYSO:Ce crystals

This paper aims at an improved understanding of luminescence properties of (Lu1−xYx)2SiO5:Ce (x=0 at%, 26 at%, 45 at%, 66 at% and 100 at%). Photoluminescence emission and excitation spectra as well as Raman spectra of (Lu1−xYx)2SiO5:Ce were investigated as a function of yttrium (shortened as Y) content in it. Obtained Huang-Rhys factor S indicates that the coupling between Ce1 (7-oxygen-coordinated), Ce2 (6-oxygen-coordinated) and LYSO lattice is intermediate and strong, respectively. Besides, it was found that: with the increase of Y content, crystal field strength around Ce1 and Ce2 decreases, Stokes shift of Ce1 and Ce2 presents an increase trend, and S of Ce2 tends to decrease. These phenomena were explained by geometrical influence of Y3+/Lu3+ on the crystal field splitting of the 5d levels of Ce3+ and coupling strength. With the increase of Y content, the evolution of S and coupling energy ħω of Ce1 present a slight increase and decrease trend respectively, while S and coupling energy ħω of Ce2 present an obvious decrease and increase trend, respectively.