Photoluminescence and energy transfer in Eu super(3+)-doped alkali gadolinium phosphates

Spectral-kinetic characteristics of the undoped and Eu super(3+)-doped alkali gadolinium phosphates of the type of MGdP sub(4)O sub(12) (M=Li, Na) have been studied within the 4.2-300K temperature range using time-resolved luminescence spectroscopy techniques. The photon cascade luminescence of Gd super(3+) ions in the undoped LiGdP sub(4)O sub(12) phosphate has been observed. In the case of the Eu super(3+)-doped MGdP sub(4)O sub(12) phosphates, no quantum cutting process takes place due to the spectral overlap of the charge transfer band of Eu super(3+) with the bands arising from the super(6)G sub()Jlevels of Gd super(3+). The processes of energy migration along the Gd super(3+) sublattice and the Gd super(3+) arrow right Eu super(3+) energy transfer have been studied. The phonon-assisted population of the Gd super(3+ 6)P sub(5/2,3/2) excited levels is suggested to be responsible for the increase in the probability of the energy migration along the Gd super(3+) sublattice via the super(6)P sub()Jstates with the subsequent energy transfer to the super(5)I sub()Jlevels of an Eu super(3+) ion.