Intrinsic fluorescence and energy transfer mechanisms in TbF3

The energy transfer mechanisms in TbF3 have been investigated. The continuous and time resolved emission and excitation spectra as well as the decays of the blue fluorescence 5D4 → 7F6, were measured at low temperature by using selective laser excitation. At 4.4 K most of the emission originates from traps while at 10 K the intrinsic fluorescence is stronger. On the basis of the experimental results a diffusion model involving shallow traps is proposed for the overall exciton to trap energy transfer process in TbF3. Finally, the validity of the model is discussed with the evaluation of the parameters, and a fast diffusion regime without direct long range energy transfers seems to be the main mechanism at low temperature.

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