The 1S0 emission from the minor site of Pr3+ in (Ba,La)F2:Pr

Abstract

In this paper we present and discuss results of detailed spectroscopy studies of Pr3+ luminescence from the (Ba,La)F2:0.2 m%Pr crystals under UV and VUV synchrotron excitation. We have measured time resolved emissions from the minor site Pr3+ in (Ba,La)F2:Pr at 10 and 300 K. The spectra clearly show the 1S0 emission from the Pr3+ ions in some low symmetry Pr-sites (we designate them La-sites) previously identified in higher concentration (0.3 m%Pr and more) crystals. However most of emission from the Pr activated (Ba,La)F2 crystals originates in Pr3+ ions in other sites which produce an efficient d-f emission. As demonstrated by excitation spectra, the emission from some of these sites (denoted as Ba-sites) closely resembles the d-f emission from BaF2. The La-site, time resolved and long delay emission spectra are dominated by hypersensitive transitions from the 1S0 and 3P0 levels to lower energy levels of the 4f2 configurations. Only these transitions contribute to the photon cascade emission desired for some mercury free phosphor applications.