Energy transfer through Gd3+ sublattice in the fluoride phosphors

Time-resolved luminescence spectra have been investigated in NaGdF4. NaY0.90Gd0.10F4 and NaGdF4:Eu3+ under ArF excimer laser (193 nm) excitation. In NaGdF4, the well-known emission lines in Gd3+ at 311 nm (P-6(7/2) --> S-8(7/2)) and 305 nm (P-6(5/2) --> S-8(7/2)) start to grow at I ts after the laser pulse and take maximum intensity at 300 mus. It is found that emissions at 313 and 307 nm decayed with a fast decay time of 3 mus. In NaY0.90Gd0.10F4, temporal changes of the emission bands are quite different from those of NaGdF4. In NaGdF4 : Eu3+, the decay time of the 311 nm emission in Gd3+ is shorter than that in NaGdF4, and some new emission lines appear at 100 mus after pulse irradiation. The energy transfer through Gd 3- sublattice is discussed. (C) 2001 Elsevier Science B.V. All rights reserved.