Propriedades fotoluminescentes, em baixa temperatura, do SrAl2O4:Eu 2+Dy3+ : efeito da concentração de dopantes

Abstract

The study of luminescent materials is a broad and important area of research, whether for the basic understanding of physical phenomena or due to various applications such as decorative items, lighting, biological imaging and computing. In this work, we investigated the photoluminescent characteristic of SrAl2O4 :Eu2+Dy3+ at low temperature, and their dependence on dopant concentration. The luminescence emission spectra were analyzed in terms of energy, using Planck's equation and the Jacobian transformation for intensities. This provided a careful analysis via curve fitting for the reproduction of the spectrum and the characterization of the luminescent bands. Emission spectra measured at 11 K confirmed the emergence of a new luminescent band at 445 nm, in addition to the 520 nm band observed at room temperature. This aspect highlights the sensitivity of the material to temperature variations. The new luminescent band was attributed to Eu2+ emission from a second non-equivalent strontium site. Variation in dopant concentration revealed a significant impact on luminescent properties, with a relationship inversely proportional to the contribution of the band at 445 nm. The analysis of the excitation spectra showed behaviors regarding the electronic transitions, allowing selective control of the green emission if excitations higher than 425 nm were used. Therefore, this study confirms and expands the understanding of the luminescent properties of SrAl2O4 :Eu2+Dy3+ , mainly its photoluminescent behavior at low temperature.