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

Abstract

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 5D0 → 7F2 transition consists of two bands peaked at 262nm and at 312nm 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 325nm the emission related to transitions from the 5D0,5D1 and 5D2 excited states of Eu3+, was observed. At pressure above 38kbar additional lines related to the transitions from the 5D3 state appeared. We found that for all pressure the emission from the 5D0 was delayed in time after excitation pulse. Emission from the 5D1 and 5D2 appeared immediately after excitation at ambient pressure and for pressure higher than 40 and 80kbar 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.