Synthesis, structural studies, electrical conductivity and optical properties of new Sb2?xLnxTe3 (Ln: Lu3+, Er3+ and Ho3+) nanomaterials

摘要

Ln-doped Sb_(2)Te_(3) (Ln: Lu~(3+), Er~(3+), Ho~(3+)) nanomaterials were synthesised by a co-reduction method in hydrothermal condition. Powder X-ray diffraction (XRD) patterns indicate that the Ln_(x) Sb_(2?)_(x) Te_(3) crystals (Ln = Lu~(3+), x = 0.00–0.06; Er~(3+) and Ho~(3+) x = 0.00–0.04) are isostructural with Sb_(2)Te_(3). The cell parameter a decreases for Ln_(x) Sb_(2?)_(x) Te_(3) compounds upon increasing the dopant content (x ), while c increases. Scanning electron microscopy and transmission electron microscopy images show that doping of Lu~(3+) and Ho~(3+) ions in the lattice of Sb_(2)Te_(3) results in spherical nanoparticles while that in Er~(3+) leads to hexagonal nanoplates, respectively. The electrical conductivity of Ln-doped Sb_(2)Te_(3) is higher than that of pure Sb_(2)Te_(3) and increases with temperature. By increasing the concentration of Ln~(3+) ions, the absorption spectrum of Sb_(2)Te_(3) shows red shifts and some intensity changes. In addition to the characteristic red emission peaks of Sb_(2)Te_(3), emission spectra of doped materials show other emission bands originating from f –f transitions of the Ho~(3+) ions.