Low temperature effects on up-conversion emission of Er3+/Yb3+ co-doped Y2O3

Abstract

Over the past years, Rare Earth (RE3+) ions doped materials have been attracted a great deal of interest due to the potential application for optical temperature sensors. Luminescence properties of these materials are sensitive and changeable with temperature. Here, we have investigated yttrium oxide doped with Yb3+ and Er3+ that was synthesized through spray pyrolysis method at 900 °C and afterwards additionally thermally treated at 1100 °C for either 12, 24 or 48h. Structural and morphological characterizations were done through X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). The obtained particles were spherical in shape and crystallized in cubic bixbyte structure with space group Ia-3. Photoluminescent measurements (PL) were recorded using the 978 nm exciting wavelength as a function of temperature in the range from 10 K to 300 K. Emission spectra are assigned to the following trivalent erbium f-f electronic transitions: 2H9/2→4I15/2 (blue: 407-420 nm), (2H11/2, 4S3/2) → 4I15/2 (green: 510-590 nm), and 4F9/2→4I15/2 (red: 640-720 nm). The fluorescent intensity ratio of the blue, green and red areas under emission bands was also examined and showed significant temperature sensitivity, with the largest value of 2.7 K-1.