Concentration Quenching of Eu3+ Fluorescence

The fluorescence quenching of the two phosphors Ba2Gd1−xEuxMe5+O6 (Me5+=Nb5+ or Ta5+) and Gd1−xEuxAl3B4O12 is reported. The shortest distance between the rare-earth sites in these materials is large and nearly equal, viz., 6.0 and 5.9 Å, respectively. The quenching behavior is different: In the materials Ba2Gd1−xEuxMe5+O6, concentration quenching occurs at x≃02, in the materials Gd1−xEuxAl3B4O12, no quenching was found under uv excitation. These results are discussed in relation to the Van Uitert—Johnson model for concentration quenching of Eu3+ fluorescence.