Charge transfer emission of ytterbium-doped oxyborates.

The ultraviolet spectroscopic properties of trivalent ytterbium have been studied at low temperature in one borate and two oxyborates in the ternary diagram Li(2)O-Y(2)O(3)-B(2)O(3). The UV luminescence was detected in the two ytterbium-doped oxyborates. The evolution of these emissions was studied as a function of the temperature. A determination of the configurational coordinate diagrams based on the Struck and Fonger model is proposed to calculate the position in energy of the charge transfer band afforded by the simulation of spectral distribution of these excitation and emission bands. The strong correlation between the luminescent properties and the environments of the rare earth is pointed out.