Investigation of the electronic structure and photoluminescence properties of Eu3+ in Sr2Mg1-xZnxSi2O7 (0≤ x ≤ 1)

Undoped and Eu3+-doped Sr2Mg1-x Zn (x) Si2O7 (0 a (c) 1/2 x a (c) 1/2 1) powder crystals were obtained by conventional solid-state reaction. X-ray diffraction, inductively coupled plasma analysis, and Fourier transform infrared spectroscopy results implied that a complete solid-solution formed between Sr2MgSi2O7 and Sr2ZnSi2O7 as well as local structural adjustment. Excitation spectra exhibited O2--Eu3+ charge transfer (CT) bands centered at 250 nm for Sr2MgSi2O7:Eu3+ and 258 nm for Sr2ZnSi2O7:Eu3+. Emission spectra exhibited a major band around 616 nm, which showed the environment around Eu3+ was non-centrosymmetric in both Sr2MgSi2O7:Eu3+ and Sr2ZnSi2O7:Eu3+. In addition, first principles calculations within the local density approximation (LDA) of density functional theory (DFT) were used to calculate the electronic structure of Sr2MgSi2O7 and Sr2ZnSi2O7. Calculated results were correlated with experimental UV-vis reflection spectra and the observed shift of the O2--Eu3+ CT band.