Optical properties and luminescence kinetics of Ln1.9Pr0.1(WO4)3 (where Ln = Gd, La) immobilized in silica xerogel

In this paper luminescent materials consisting of Ln(1.9)Pr(0.1)(WO4)(3) where Ln = Gd or La immobilized in silica xerogel matrix have been obtained through a sol-gel approach. The spectroscopic investigations of these materials are presented. Steady state luminescence, luminescence excitation spectra as well as time resolved emission spectra have been measured. The obtained strong red emission due to the excitation energy transfer from WO42- group to Pr(III) ion upon excitation at lambda(exc) = 240 nm is the main result of this paper. Analysis of the luminescence kinetics of Pr(III) ions in studied materials has been performed. The decay curves of Pr(III) luminescence related to P-3(0) -> H-3(4) and P-3(0) -> F-3(2) transitions are reported. High emission intensity and easy preparation of these materials make them promising red phosphors for applications as luminescent materials. (C) 2011 Elsevier B.V. All rights reserved.