Energy migration processes in phosphate nanocrystals: Size and dimensionality dependence

Abstract

Peculiarities of electronic excitation energy migration in phosphate nanocrystals with three-dimensional (EuPO 4 ) and one-dimensional (EuP 3 O 9 ) arrangement of regular ions under variation of concentration of both energy traps (Nd 3+ ions) and scattering centres (La 3+ ions) are discussed in the paper. Processes of energy migration in both EuPO 4 and EuP 3 O 9 nanocrystals are phonon-assisted ones due to absence of resonance between energy levels of adjacent Eu 3+ ions. The distance of energy migration for both EuPO 4 and EuP 3 O 9 nanocrystals was found to be equal to tens of nanometres, however, for EuPO 4 nanocrystals energy migration leads to stronger quenching of Eu 3+ luminescence. For 10 nm EuPO 4 nanocrystals sufficient hampering of energy migration is observed due to the depletion of the low-energy phonon spectrum as a result of the phonon confinement effect.