Nanosecond fluctuation kinetics of luminescence hopping quenching originated from the 5d1 level in the Ce3+:YPO4·0.8H2O nanocrystals

We study the nanosecond energy transfer kinetics detected at dipole allowed 5d1–4f1 transition and originated from the lowest 2Γ1 level of the Ce3+ ions doped into the rhabdophane-type YPO4·0.8H2O nanocrystals synthesized by microwave hydrothermal treatment. We show that the luminescence quenching in the nanocrystals is determined by two processes depending on Ce3+ (energy donor) concentration at constant OH− (energy acceptors) concentration. At 0.2 mol% Ce3+ the luminescence quenching is mainly determined by direct (static) quenching caused by vibrations of OH− groups. At 2.0 mol% Ce3+ the quenching accelerates due to energy migration from the Ce3+ ions with poor acceptor surrounding to the Ce3+ ions with the nearby OH− acceptors. In the latter case we observe fluctuation kinetics of the luminescence impurity hopping quenching starting immediately after static ordered stage of the decay kinetics. We obtain that for dipole allowed the 5d–4f transition in the Ce3+ donor the CDD microparameter of the Ce3+–Ce3+ energy migration and CDA microparameter of Ce3+–OH− energy transfer are in strong correlation with the higher spontaneous emission rate for dipole allowed transition in Ce3+ comparing to dipole forbidden transition in Nd3+.