ZnAl2O4 co-doped with Yb3+/Er3+ prepared by combustion reaction: evaluation of photophysical properties

Zinc aluminate co-doped with Yb3+/Er3+ for potential application in upconversion lasers was prepared in proportions of 2:1, 5:1, and 10:1 by combustion reaction. The samples were characterized by X-ray diffraction, transmission electron microscopy, and optical spectroscopy. The results reveal the formation of crystalline ZnAl2O4 primary phase and trace amounts of ZnO and Yb3Al5O12 secondary phases. They also indicate that increasing the Yb3+/Er3+ ratio favored the increase of secondary phases. The optical spectroscopy analysis revealed that red emission predominated over green, and that emission intensity was directly influenced by the infrared intensity of the diode laser. These results indicate that ZnAl2O4 doped with rare earth ions may also be an interesting material for luminescence obtained by energy upconversion.