Síntese por reação de combustão, caracterização e propriedades luminescentes do aluminato de zinco (ZnAl2O4) dopado com íons terras raras Eu3+ e Tb3+.

Abstract

This work proposes the obtaining of powders of rare earth ions doped zinc aluminate, using the synthesis for combustion reaction, method that stands out for its simplicity, low cost and capacity of obtaining of crystalline powders with high purity and chemical homogeneity. The zinc aluminate was chosen as head office for the rare earth ions, due to its high thermal stability and transparency for wave lengths in the strip of visible light. Due to the interesting optical properties of the rare earth elements, such as: emission spectra presenting fine bands, length of emission wave and long time of florescent life, the produced powders presented interesting properties for photoluminescent applications, as phosphors in displays of high efficiency. They were used for the doped the ions rare earth Eu3 + and Tb3 +, emitting respectively color-shines them, red and green in bands with particularly fine ghastly widths, typical of the elements rare lands, when excited by means of ultraviolet radiation. It was verified that the increase of the doped concentration in the head office increases the luminescence intensity. Contrary effect happens when if I reached a concentration it criticizes of doped, that is to say, concentration where distances it among ions doped in the head office reaches a value I criticize (I stripe I criticize), below this value the effect of the solemnity-suppression, that consists of the transfer of energy among ions of same species without the emission of visible light, decreases the intensity of luminescence of the powders gradually. The doped addition in more significant amounts provided the formation of secondary phase, due to the low solubility of the ions rare lands in the crystalline head office.