Energy transfer in Pr3+ and Mn2+ co-doped SrB6O10 and SrB4O7

The luminescent properties of Pr3+ and Mn2+-doped SrB6O10 and SrB4O7 powder samples were investigated from the point of view of energy transfer between Pr3+ and Mn2+. The emission from the 1S0 level of Pr3+ was found in the SrB6O10:Pr3+ sample as well as in the SrB4O7:Pr3+ sample, indicating the 1S0 level is below the lowest 4f5d energy level in these hosts. The spectral overlaps between the emission spectra of Pr3+-doped samples and the excitation spectra of Mn2+-doped sample were found in both kinds of strontium borates. These spectral overlaps are in favor of the energy transfer from Pr3+ to Mn2+. However, in the emission spectra of the SrB6O10:Pr3+, Mn2+, no indication of energy transfer was observed, though the emission spectra of SrB4O7:Pr3+, Mn2+ did show evidence of energy transfer from Pr3+ to Mn2+. The possible reasons were discussed.