DETERMINATION OF THE OPTIMUM EU3-CONCENTRATION IN LAALO3 - EU-PHOSPHORS BY X-RAY-DIFFRACTION AND FLUORESCENCE MEASUREMENTS()

Combining X-ray powder diffraction with fluorescence measurements is a n efficient way to determine the optimum activator concentration of in organic phosphors. La1-xEuxAlO3 samples (perowskite structure), prepar ed by solid state reactions with 0.5 < x < 5.0 at 1480 K, were investi gated by both analytical methods. The luminescence emission spectra sh ow strong 5D0-F-7(1) and 5D0-7D2 transitions and fluorescence intensit y reaches a maximum at 1 mol% Eu3+. X-ray diffraction shows the format ion of an EuAlO3 phase at Eu3+ concentrations above 1 mol%. Below 1 mo l%, Eu3+ substitutes for La3+, as can be seen from the change in the l attice constant c.