Molecular Construction Using (C₃N₃O₃)^3– Anions: Analysis and Prospect for Inorganic Metal Cyanurates Nonlinear Optical Materials

Molecular construction using good optically active microscopic units is vital to efficiently explore good nonlinear optical (NLO) materials, a type of important optoelectronic functional materials. In this work, we highlight the planar (C 3 N 3 O 3 ) 3– anion, the main fundamental building block in inorganic metal cyanurates, as an outstanding candidate of building blocks for NLO materials. Several noncentrosymmetric metal cyanurates containing the (C 3 N 3 O 3 ) 3– groups are studied by the first-principles calculations for the first time. It is shown that these materials possess wide band gaps ( E g > 5.5 eV), high SHG coefficients ( d 22 > 2 × BBO), and large birefringence values (Δ n > 0.1) and thus have good potentials in the ultraviolet NLO applications. Moreover, the key role of the (C 3 N 3 O 3 ) 3– groups to the good NLO performance in the cyanurates is elucidated. On the basis of the first-principles analysis, some possible searching directions of good NLO materials containing (C 3 N 3 O 3 ) 3– groups are proposed.