Na4yb(Co3)3f: A new uv nonlinear optical material with a large second harmonic generation response

Abstract

A new nonlinear optical crystals fluoride carbonate, Na4Yb(CO3)3F, has been synthesized by mild hydrothermal method. The Na4Yb(CO3)3F crystallizes in the noncentrosymmetric space group Cc (no. 9) with the lattice parameters a = 8.018(3), b = 15.929(5), c = 13.950(5) Å and β = 101.425(6)◦ . The compound Na4Yb(CO3)3F has a high density of [CO3] groups. The structure can be described as one-dimensional [Na5Yb(CO3)2F2] chains connected by [CO3] groups, forming an intricate three-dimensional (3D) framework. Other Na+ and Yb3+ cations are located in the cavities of 3D network. The powder second harmonic generation (SHG) measurement shows that Na4Yb(CO3)3F features a large SHG response, about 4.3 times that of KH2PO4 (KDP), and is a phase-matchable material. In addition, its UV-Vis-NIR diffuse reflectance spectral data indicate that Na4Yb(CO3)3F has a large optical gap about 4.72 eV, which corresponds to the UV cut-off edge of 263 nm.