Peculiarities of excitation of Ce-emission in core region of chlorine perovskites

Abstract

Excitation spectra of Ce-doped KCaCl3, RbCaCl3, CsSrCl3 and CsCaCl3 crystals were studied at 300 and 9K in the 4–35eV spectral range using synchrotron radiation. Peculiarities of the excitation spectra in the region of the uppermost core are considered from the view point of feasibility of the energy transfer from the core excitons and holes to Ce-centers. The possible channels for excitation of the activator luminescence are assumed for the CsCaCl3 and CsSrCl3 crystals exhibiting core-valence luminescence (CVL) as follows: (i) the reabsorption of the CVL by Ce-centers; (ii) the creation of the valence holes on account of radiative decay of core excitations via CVL and (iii) the migration of the core holes. All these schemes are distinctly impossible for the CVL-free KCaCl3 and RbCaCl3 crystals where core excitations decay just through the non radiative Auger-process.