Luminescence of BAM under high pressure: the Eu2+ sites

BaMgAl10O17:Eu2+ is an important blue phosphor in lamps and plasma displays with a close to unity quantum yield. A number of experiments have indicated that Eu2+ may reside on as many as three different sites. The Eu2+ emission is studied as a function of pressure for a series of UV excitation wavelengths. The resulting emission, which turns from blue to blue-green at the highest pressures, is fit with the sum of three Gaussians whose positions are a function of pressure and whose relative intensities are a function of excitation wavelength. A fit for pressures up to 150 kbar and excitation wavelengths from 275 to 363 nm yields a self- consistent result for the pressure dependence of the transition energies for the three bands. The Eu2+ site distribution is discussed in light of the results of the pressure dependence.