Decay kinetics of the triplet luminescence from self‐trapped excitons in CdMoO 4 and ZnWO 4

Decay kinetics of the intrinsic luminescence from the triplet excited state of self‐trapped excitons in CdMoO 4 and ZnWO 4 has been investigated in a wide temperature range between 7 and 300 K. The measurements are carried out under low‐density excitation with the fourth harmonics (266 nm) of a Nd:YAG laser. The decay curves show two decay components, fast and slow, at T  < 40 K in CdMoO 4 and at T  < 15 K in ZnWO 4 . At higher temperatures, the decay curves in both materials are well described by single‐exponential functions. A three‐level model consisting of two excited states separated by an energy D and a ground state is applied to explain the temperature dependences of fast and slow decay times. From the fit to the experimental data, we obtain D  = 3.7 ± 0.5 meV for CdMoO 4 and 2.1 ± 0.3 meV for ZnWO 4 .