Explanation of anomalous heating rate dependence of thermoluminescence in YPO4:Ce3+,Sm3+ based on the semi-localized transition (SLT) model

In thermoluminescence (TL) measurements radiative recombination takes place at various temperatures. Thermal quenching, if present, decreases intensity of luminescence at elevated temperatures. Therefore, with increasing heating rate, we expect decrease of the total number of emitted photons. Recently, Bos et al. (2010) observed quite different behaviour in YPO4:Ce3+,Sm3+. This paper presents a possible explanation of this phenomenon based on the model of semi-localized transitions (SLT).

► YPO4:Ce3+, Sm3+ exhibits anomalous heating-rate dependence of thermoluminescence.
► Energy scheme for YPO4:Ce3+, Sm3+ resambles the model of semi-localized transitions.
► Numerical calculations of TL in SLT model were done using known Sm2+ trap energies.
► The SLT predictions well agree with experimental data.