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

This paper reports the preparation and characterization of erbium oxalate a nd erbium oxide nanoparticles. The erbium oxalate and erbium oxide phosphor materials were synthesized through the microemulsion technique. Transmissi on electron microscopy (TEM) was used to characterize the phosphor material s and reveal a nanocrystal structure for the studied phosphors. A strong gr een up-conversion emission at 543 nm (S-4(3/2) --> I-4(15/2)) and another w eak 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 gre en up-conversion emission equally strong in both the phosphors and for thes e phosphors, color coordinates ( X, Y) have been obtained in order to asses s their color emitting efficiency. (C) 2001 Elsevier Science B.V. All right s reserved.