The effects of precursor concentration and morphology on photoluminescence behavior of Tb₂O₃ phosphors

Abstract

Terbium oxide (Tb 2 O 3 ) phosphors were prepared the using sol-precipitation method with the use of different precursor concentrations. The X-ray diffraction (XRD) patterns showed C-type body-centered cubic phase, space group Ia-3, and the crystallite size values were found in the range of 19.45-32.34 nm depending on the solution composition and calcination temperature. As the crystallinity increased, the defects in the structure decreased, that is, the dislocation density decreased. Under the excitation at 325 nm, although all the Tb 2 O 3 phosphors emitted a single peak around 544 nm ( 5 D 4 -7 F 5 transition) in PL spectra, when the peak was enlarged, the presence of additional peaks shifted to the red/blue region was also observed. The color chromaticity coordinates showed that it exhibited different tones of emission from light yellow to green depending on the precursor concentration and calcination temperature. With increasing the precursor concentration, nucleation rate increased and the particle shape changed from nearly spherical to rod-like. They may be promising for laser devices and display applications due to their strong green emission.