Lu3+/Yb3+ and Lu3+/Er3+ co-doped antimony selenide nanomaterials: synthesis, characterization, and electrical, thermoelectrical, and optical properties

Lu3+/Yb3+ and Lu3+/Er3+ co-doped Sb2Se3 nanomaterials were synthesized by co-reduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that the LnxLn'xSb2-2xSe3 Ln: Lu3+/Yb3+ and Lu3+/Er3+ crystals (x = 0.00 - 0.04) are isostructural with Sb2Se3. The cell parameters were increased for compounds upon increasing the dopant content (x). Scanning electron microscopy and transmission electron microscopy images show that co-doping of Lu3+/Yb3+ ions in the lattice of Sb2Se3 produces nanorods, while that in Lu3+/Er3+ produces nanoparticles, respectively. The electrical conductivity of co-doped Sb2Se3 is higher than that of the pure Sb2Se3 and increases with temperature. By increasing the concentration of Ln3+ions, the absorption spectrum of Sb2Se3 shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb2Se3, emission spectra of co-doped materials show other emission bands originating from f-f transitions of the Yb3+ ions.