Quantitative Determination of Nonradiative Host-to-Activator Energy Transfer Efficiencies in YBO3:Eu3+ and Y2O3:Eu3+ under Vacuum Ultraviolet Excitation

We report on the spectroscopic determination of nonradiative host to activator transfer efficiencies in Eu 3+ -doped Y 2 O 3 and YBO 3 under vacuum ultraviolet excitation. The calculation of transfer efficiency is described, and the transfer efficiency behavior of both hosts is assessed in terms of accepted energy flow models. From our measurements we have concluded that electron−hole pair mobility is greater in Y 2 O 3 than in YBO 3 and that the primary reason for the relatively low efficiency of Y 2 O 3:Eu 3+ under 147 nm excitation is loss of excitation energy to surface states. Measurements on the Tm 3+ -doped hosts indicate that these properties are features of the host rather than of the dopant.