Second-order nonlinear optical-active selenide borate Zn8Se2(BO2)12: Experimental and theoretical analysis

Inorganic compounds with mixed anions attract broad interest recently in view of their rich structural chemistry and physical performance. Specifically, chalcogenide borates are receiving increasing attention though they are in their infancy. Here, the chalcogenide borate Zn₈Se₂(BO₂)₁₂ is revisited by focusing on its second-harmonic generation (SHG) activity. Its sodalite cage structure is elucidated in detail and correlates with the SHG behavior. Its optical band gap is determined to be 4.42 eV. Theoretical calculations on its electronic structure and optical properties are performed and the results are well consistent with the experimental ones. Besides, the structural chemistry with related structures and possible SHG improvement strategies are discussed.