Luminescence of borates with yttrium and lutetium cations

This paper reports on the results of an investigation into the luminescence properties of yttrium and lutetium borates, as well as the Y$_{0.35}$Lu$_{0.65}$BO$_3$ solid solution, under excitation with the synchrotron radiation in the X-ray and ultraviolet spectral ranges. It has been shown that there exists an intrinsic luminescence band in the ultraviolet spectral range 260–270 nm due to the luminescence of self-trapped excitons. It has been found that the kinetic characteristics of this band depend on the density of the exciting synchrotron radiation. A number of luminescence bands have been observed in the long-wavelength range due to the presence of defects in the crystal structure of borates. It has also been shown that the energy transfer to impurity centers has a recombination nature and can also occur through impact ionization of defects. It has been revealed that, for the solid solution, the excitation efficiency of the luminescence of defects increases under interband excitation, which can be associated with the limited separation of the components of an electron-hole pair as a result of short-range order disturbance in the structure of the solid solution.