Photoluminescence of CaGa2S4:Pr Polycrystals

Abstract

The photoluminescence (PL) and PL excitation spectra of CaGa₂S₄ polycrystals doped with praseodymium are studied in the regions of the activator absorption and the fundamental absorption of the host. It is found that the PL excitation spectrum consists of two regions: broadband absorption in the range of 200-380 nm corresponding to the fundamental absorption of the host and the narrow-band absorption of the dopant in the range of 430–515 nm. The luminescence spectra are different for different excitation wave-lengths, which occurs because Pr³⁺ ions substitute divalent cations occupying different crystallographic positions in the host crystal lattice.