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

Abstract

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 of P4¯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→4f7 transition. 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.