The energy transfer processes in LaMgB5O10:Pr3+, Mn2+

Pr3+, Mn2+ singly doped and co-doped LaMgB5O10 samples were prepared by solid-state reaction and their spectroscopic properties were investigated by synchrotron radiation VUV light. Significant spectra overlap between the Mn2+ (6)A(1g) --> (E-4(g), (4)A(1g)) excitation (centered at 412 nm) and the Pr3+ S-1(0) --> (I-1(6), P-3(J)) emission (4 10 nm) provided the possibility of energy transfer from Pr3+ to Mn2+. In the LaMgB5O10:Pr3+, Mn2+ samples investigated, the expected energy transfer process was observed as comparing the emission spectra of LaMgB5O10:Pr3+, Mn2+ samples with that of the LaMgB5O10:Mn2+. The shorter decay time of the S-1(0) --> (I-1(6), (3)p(J)) transition in the co-doped samples was also an evidence of energy transfer from Pr3+ to Mn2+. By analyzing the energy transfer process, it was found that the energy transfer process in LaMgB5O10:Pr3+, Mn2+ was likely of resonant energy transfer and the re-absorption process can be excluded. The critical distances of energy transfer based on the electric dipole-dipole interaction and electric dipole-quadrupole interaction were calculated to be 4.78 and 9.46 angstrom in LaMgB5O10:Pr3+, Mn2+, respectively, which are smaller than the mean distance of Pr3+ and Mn2+ (17 angstrom) in the highest concentration-doped sample. The near neighboring Pr-Mn clusters formed in the LaMgB5O10 host is responsible for the energy transfer process. (C) 2007 Elsevier Ltd. All rights reserved.