Photoluminescence of CaS:Eu 2+ under hydrostatic pressure

Abstract

We have studied the hydrostatic pressure dependence of the emission of CaS doped with Eu 2+. For P ≥ 70 kbar, we observed the main the emission peak broadens and appears to 'split' into two peaks with the low-energy peak increasing in intensity relative to the main energy peak. We proposed that more than one excited state could be thermally populated at room temperature. The quenching of the luminescence can be explained by the presence of an intervening state using a single configuration coordinate model. © 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.