Spectral characteristics and energy transfer from Ce3+ to Tb3+ in compounds Lu1 – x – yCexTbyBO3

Resumo

The structure, IR absorption spectra, morphology, and spectral characteristics of compounds Lu_{1 – x – y}Ce_xTb_yBO₃ have been investigated. It has been shown that the Tb³⁺ luminescence excitation spectrum of the Lu_{1 – x – y}Ce_xTb_yBO₃ compounds is dominated by a broad band coinciding with the excitation band of Ce³⁺ ions, which clearly indicates energy transfer from the Ce³⁺ ions to the Tb³⁺ ions. The spectral position of this band depends on the structural state of the sample: in the structures of calcite and vaterite, the band has maxima at ~339 and ~367 nm, respectively. By varying the ratio between the calcite and vaterite phases in the sample, it is possible to purposefully change the Tb³⁺ luminescence excitation spectrum, which is important for the optimization of the spectral characteristics of Lu_{1 – x – y}Ce_xTb_yBO₃ when it is used in light-emitting diode sources. An estimate has been obtained for the maximum distance between Ce³⁺ and Tb³⁺ ions, which corresponds to electronic excitation energy transfer. It has been shown that the high intensity of Tb³⁺ luminescence in these compounds is due to the high efficiency of electronic excitation energy transfer from the Ce³⁺ ions to the Tb³⁺ ions as a result of the dipole–dipole interaction.