Study on the mechanism of improved luminescence in SrB2Si2O8: Ce3+/Tb3+ phosphor

Abstract

SrB2Si2O8: Tb3+ and SrB2Si2O8: Ce3+, Tb3+ phosphors were synthesized through conventional high temperature solid state reaction method. Under near ultraviolet (NUV) excitation of 377 nm, the emission peaks of the SrB2Si2O8: Tb3+ green phosphor located at 489, 544, 585 and 623 nm corresponding to Tb3+ ions energy level transition of 5D4 excitation state to 7F6, 7F5, 7F4 and 7F3 ground states, respectively. The optimal concentration of Tb3+ ions is 11at.%, and the concentration quenching mechanism can be interpreted by the dipole-quadrupole interaction of Tb3+ ions. For the Sr1-xB2Si2O8: Ce3+, xTb3+ phosphors, the maximum luminescence intensity is 21 times higher than that of the single doped Tb3+, which originates from the energy transfer of Ce3+ to Tb3+ ions. The energy transfer efficiency is calculated to be 79.7%, which is caused by the dipole-dipole resonant type. The CIE coordinates of SrB2Si2O8: Ce3+, Tb3+ phosphors change from blue (0.167, 0.071) to green (0.241, 0.546). When the temperature reaches 210 °C, the luminescence intensity reaches 72.20% of the initial value, indicating that the materials have good thermal stability. The above consequences demonstrate that the SrB2Si2O8: Ce3+, Tb3+ phosphors can be used as a candidate for a promising green luminescent phosphor in ultraviolet excited W-LEDs.