Australia's Defence

The Mechanism of the Emission Color Shift with Activator Concentration in +3 Activated Phosphors

“…These results indicate that below these activator concentrations Eq. [1] and [2] can apply to analysis of the experimental data. The Io~,/x data of the 5D1 and 5D2 emissions, over the activator concentration range of 021 to 0.1 mole fraction, fit on straight lines whose slopes are respectively 6/3 and 8/3 which indicate that dipoledipole and dipole-quadrupole interactions are involved in the concentration quenching mechanism of the 5D1 and 5D2 emissions, respectively.…”

“…The emission of Eu +3 activated phosphors usually results from three excited states, namely '~D._, (bluegreen), 5D1 (green-orange), 5D0 (red) and the emission color shifts from yellow to red with an increase in activator concentration (1)(2)(3) and/or in the phosphor temperature (4)(5)(6).…”

“…For strongly absorbed exciting radiation, however, the observed concentration dependence curve, (Iob/X) vs. x, deviates from the curves calculated by Eq. [1] and [2]. Equations [1] and [2] apply only to weakly absorbed exciting radiation used here (10).…”