Luminescence Properties of Green Phosphor Ca2Ga2(Ge1-xSix)O7:y%Eu2+ and Application

Rare earth luminescent materials demonstrate significant advantages in lighting and energy saving, and detection etc. In this paper, a series of Ca2Ga2(Ge1-xSix)O7:y%Eu2+phosphors were synthesized by high-temperature solid-state reaction and characterized by X-ray diffraction and luminescence spectroscopy methods. The powder X-ray diffraction patterns reveal that all the phosphors are isostructural with a space group ofP4¯21m. The excitation spectra of Ca2Ga2(Ge1-xSix)O7:1%Eu2+phosphors exhibit significant overlapping of the host and the Eu2+absorption bands, which facilitates Eu2+absorbing the energy to increase its luminescence efficiency when excited by visible photons. The emission spectra show that the Eu2+doped phosphors have a broad emission band with a peak centered at 510 nm arising from the 4f65d1→4f7transition. Variable temperature fluorescence reveals that the phosphor has a strong luminescence at low temperature but has a severe thermal quenching effect when temperature rises. The optimal Ca2Ga2(Ge0.5Si0.5)O7:1.0%Eu2+phosphor shows promise for application in the field of fingerprint identification based on the experimental results.