Preparation and characterization of erbium oxalate and erbium oxide nanoparticles by microemulsion technique

This paper reports the preparation and characterization of erbium oxalate and erbium oxide nanoparticles. The erbium oxalate and erbium oxide phosphor materials were synthesized through the microemulsion technique. Transmission electron microscopy (TEM) was used to characterize the phosphor materials and reveal a nanocrystal structure for the studied phosphors. A strong green up-conversion emission at 543 nm (S-4(3/2) --> I-4(15/2)) and another weak emission at 528 nm (H-2(11/2) --> I-4(15/2)) have been measured for the studied phosphors upon excitation at 993 nm (I-4(11/2) --> I-4(15/2)). The up-conversion emission mechanism has been explained by means of an energy level diagram. The lifetimes of these emissions have been measured. The green up-conversion emission equally strong in both the phosphors and for these phosphors, color coordinates ( X, Y) have been obtained in order to assess their color emitting efficiency. (C) 2001 Elsevier Science B.V. All rights reserved.