Lu^sup 3+^/Yb^sup 3+^ and Lu^sup 3+^/Er^sup 3+^ co-doped antimony selenide nanomaterials: synthesis, characterization, and electrical, thermoelectrical, and optical properties

Abstract

Lu^sup 3+^/Yb^sup 3+^ and Lu^sup 3+^/Er^sup 3+^ co-doped Sb^sub 2^Se^sub 3^ nanomaterials were synthesized by co-reduction method in hydrothermal condition. Powder X-ray diffraction patterns indicate that the Ln^sub x^Ln^sup '^ ^sub x^Sb^sub 2-2x^Se^sub 3^ Ln: Lu^sup 3+^/Yb^sup 3+^ and Lu^sup 3+^/Er^sup 3+^ crystals (x = 0.00 - 0.04) are isostructural with Sb^sub 2^Se^sub 3^. 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 Lu^sup 3+^/Yb^sup 3+^ ions in the lattice of Sb^sub 2^Se^sub 3^ produces nanorods, while that in Lu^sup 3+^/Er^sup 3+^ produces nanoparticles, respectively. The electrical conductivity of co-doped Sb^sub 2^Se^sub 3^ is higher than that of the pure Sb^sub 2^Se^sub 3^ and increases with temperature. By increasing the concentration of Ln^sup 3+^ions, the absorption spectrum of Sb^sub 2^Se^sub 3^ shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb^sub 2^Se^sub 3^, emission spectra of co-doped materials show other emission bands originating from f-f transitions of the Yb^sup 3+^ ions.