Double-perovskite compound Na2ZrTeO6: Synthesis, structure and self-activated near-infrared luminescence.

Perovskite compounds are always the focus in the material research field. Herein, the polycrystalline samples and single crystals of Na 2 ZrTeO 6 , a B-site ordered double-perovskite compound, were prepared successfully. Single crystal X-ray diffraction demonstrated that Na 2 ZrTeO 6 crystallizes in the cubic space group Fm-3m (No. 225) with unit parameters of a = b = c = 7.80360(10) Å. The crystal structure of Na 2 ZrTeO 6 , formed by ZrO 6 and TeO 6 octahedra through sharing the corner oxygen atoms, belongs to the typical rock-salt-type perovskite structure. The density functional theory calculations show that Na 2 ZrTeO 6 has a direct band gap with band gap of 3.21 eV, which is lower than the experimental value of 3.85 eV. Interestingly, the powder samples of Na 2 ZrTeO 6 exhibit a self-activated near-infrared emission centered at 780 nm under ultraviolet light excitation. And a strong luminescence thermal stability was also observed. Compared to room temperature, the luminescence intensity can maintain 64 % at 200 °C. [Display omitted] • The high-purity double-perovskite Na 2 ZrTeO 6 samples were synthesized by wet chemical method. • Structure analysis indicate that Na 2 ZrTeO 6 belongs to the typical rock-salt-type perovskite structure. • Na 2 ZrTeO 6 exhibits self-activated near-infrared emission centered at 780 nm excited by 308 nm. • The sample's emission intensity maintained 64 % of its room temperature peak intensity at 200 °C. [ABSTRACT FROM AUTHOR]