Kononets N. The processes of electron excitation energy migration in borate and phosphate nanocrystals with different anisotropy of arrangement of regular ions

The influence of the dimensionality of the system of regular rare earth ions on the processes of electron excitation energy migration in ReMgB5O10, ReAl2.07(B4O10)O0.6, ReAl3(BO3)4, RePO4, ReP3O9 (Re = Eu, La, Nd) nanocrystals was determined. It was shown that energy migration in EuMgB5O10 nanocrystals occurs strictly along the Eu3+ ion chains. For EuAl2.07(B4O10)O0.6 and EuAl3(BO3)4 nanocrystals it was determined that despite the shorter distances between adjacent Eu3+-Eu3+ ions in EuAl2.07(B4O10)O0.6 nanocrystals, energy migration leads to less pronounced luminescence quenching due to the different dimensionality of systems of rare earth ions in these nanocrystals. Studies carried out for EuPO4 and EuP3O9 nanocrystals have shown that while for EuPO4 energy migration can occur both with the participation of dipole-dipole and exchange interaction, for EuP3O9 energy migration takes place by exchange interaction in all the studied range of temperatures (10 - 293 К). Using EuPO4 nanocrystals of different sizes (10 nm and 100 nm), it was shown that decrease in the size of nanocrystals leads to the slowdown in the processes of migration of electron excitation energy due to modification of low-frequency phonon spectra of nanocrystal.