Up-Conversion Behavior of Er³⁺/Yb³⁺-Activated Gd₂O₃ Phosphor for Magnetic Resonance Application

We present new aspects of erbium- or ytterbium-doped pure gadolinium oxide (Gd₂O₃:Er³⁺/Yb³⁺) as a suitable candidate for drug delivery and magnetic resonance (MR) applications. The samples were prepared using the conventional sol–gel synthesis technique. The structural studies revealed that the prepared sample was monophased and crystallizes in a cubic structure. FTIR measurements confirmed the creation of Gd₂O₃:Er³⁺/Yb³⁺ phosphor. SEM micrographs clearly indicated that the particles crystallized in uniform shape, exhibiting nano-rod formation, with the particle size ranging from 55 to 5 nm. TEM images revealed that Er³⁺- and Yb³⁺-co-doped Gd₂O₃ nanoparticles were the collection of the nano-rods 2–4 nm thick and 18–20 nm long. Also, photoluminescence analysis of the phosphor samples for variable concentrations of doping ions was presented. When doped with Er³⁺/Yb³⁺, nano-rod Gd₂O₃ emits intense green emission and some red emission peaks, under a 980-nm near-infrared laser. Our study shows that as-prepared samples may be useful for optical imaging systems and that nano-rod formation may be used as a major host carrier for drug delivery.