Optical and dielectric properties of NaCoPO4 in the three phases α, β and γ

A Ajmi; K Karoui; K Khirouni; A Ben Rhaiem

doi:10.1039/c9ra01558b

Optical and dielectric properties of NaCoPO₄ in the three phases α, β and γ

RSC Adv. 2019 May 14;9(26):14772-14781. doi: 10.1039/c9ra01558b. eCollection 2019 May 9.

Authors

A Ajmi¹, K Karoui¹, K Khirouni², A Ben Rhaiem¹

Affiliations

¹ Laboratory LaSCOM, University of Sfax BP1171 3000 Sfax Tunisia abdallahrhaiem@yahoo.fr.
² Laboratory of Inorganic Chemistry, University of Sfax BP1171 3000 Sfax Tunisia.

Abstract

In this work, we are interested in the synthesis of monophosphate α-NaCoPO₄, β-NaCoPO₄ and γ-NaCoPO₄ compounds by mechanochemical method and their characterization by X-ray powder diffraction patterns. These compounds are crystallized in the orthorhombic, hexagonal and monoclinic system, in Pnma, P6₅ and P2₁/n space groups, respectively. The optical properties were measured by means of the UV-vis absorption spectrometry in order to deduce the absorption coefficient α and optical band gap E _g. The calculated values of the indirect band gaps (E _gi) for three samples were estimated at 4.71 eV, 4.63 eV and 3.8 for compounds α, β and γ, respectively. The Tauc model was used to determine the optical gap energy of the synthesized compounds. Then, the results of the dielectric proprieties measured by varying the frequency are described.