Improvable luminescent properties by adjusting silicon–calcium stoichiometric ratio in long afterglow phosphors Ca 1.94 MgSi 2 O 7 :Eu2+0.01

Abstract The Ca1.94MgSi2O7: Eu 2 + 0 . 01 , Dy 3 + 0.05 long afterglow phosphors with different silicon–calcium stoichiometric ratios (Si/Ca = 1, 1.1, 1.2, 1.3 and 1.4) were successfully prepared under a reducing atmosphere by solid-state reaction method. The X-ray diffraction data indicate that bridging oxygen can be formed relatively easily with the increase of silicon–calcium stoichiometric ratio, which is beneficial to generating Ca2MgSi2O7, even the CaMgSi2O6 phase. Moreover, increasing the silicon–calcium stoichiometric ratio in a proper way not only reduces the sintering temperature, but also enhances the photoluminescence intensity. The afterglow properties are also improved by adjusting the silicon–calcium stoichiometric ratio, which is due to the formation of O vacancies and the codoping of Dy3+. These new insights into the Ca1.94MgSi2O7: Eu 2 + 0 . 01 , Dy 3 + 0.05 phosphors with different silicon–calcium stoichiometric ratios are useful for synthesizing single akermanite phase, reducing sintering temperature and improving luminescent properties, thereby motivating the long afterglow phosphors Ca1.94MgSi2O7: Eu 2 + 0 . 01 , Dy 3 + 0.05 available for commercial use.