Luminescence of heavily Ce-doped alkaline-earth fluorides

The spectral and kinetic parameters of M(1-x)Ce(x)F(2+x) (x = 0.35, M = Ca, Sr, Ba) crystals luminescence have been studied. These characteristics are compared to the luminescence of solution base hosts: MF(2):Ce and CeF(3), The emission bands of heavily Ce-doped alkali earth fluorides are closed to the spectrum of perturbed Ce-center in CeF(3) at T = 9 K. Luminescence of M(0.65)Ce(0.35)F(2.35) crystals reveals the efficient excitation in the UV and VUV ranges. The main feature of the emission and excitation spectra of Ce(3+) luminescence is the displacement to the low-energy range according to the bandgap decrease in the Ca-, Sr- and Ba-based fluorides, respectively. Small Stokes shift leads to the reabsorption and light yield decrease. Luminescence peculiarities of M(1-x)Ce(x)F(2+x) solid solution and the role of Ce-enriched inclusions are discussed. (c) 2009 Elsevier B.V. All rights reserved.