High pressure effect on charge transfer transition in Y2O2S:Eu3+

In this contribution, spectroscopic characterization of Y2O2S doped with 1 mol% of Eu3+ are presented. Steady state luminescence and luminescence excitation spectra, as well as the time resolved spectra and luminescence kinetics were measured. All experiments were performed at ambient and high hydrostatic pressure up to 240 kbar applied in diamond anvil cell (DAC). The excitation spectrum of the Eu3+ emission monitored at D-5(0) -> F-7(2) transition consists of two bands peaked at 262 nm and at 312 nm that can be attributed to host lattice absorption and to charge transfer (CT) transition (O2- -> Eu3+ and S2- -> Eu3+), respectively. At ambient pressure under excitation 325 nm the emission related to transitions from the D-5(0), D-5(1) and D-5(2) excited states of Eu3+, was observed. At pressure above 38 kbar additional lines related to the transitions from the D-5(3) state appeared. We found that for all pressure the emission from the D-5(0) was delayed in time after excitation pulse. Emission from the D-5(1) and D-5(2) appeared immediately after excitation at ambient pressure and for pressure higher than 40 and 80 kbar was delayed in time. Analysis of pressure induced changes in Eu3+ luminescence kinetics allowed to develop the quantitative configurational coordinated model of the Y2O2S:Eu3+ system. (C) 2013 Elsevier B.V. All rights reserved.