Aliovalent-substituted synthesis for a non-centrosymmetric phosphate with enhanced nonlinear-optical response

Non-centrosymmetric structure is the most important prerequisite for a nonlinear-optical (NLO) material. Herein, a non-centrosymmetric phosphate LiRb2Y2(PO4)3 (1), which is transparent down to ultraviolet region, was synthesized by the high-temperature solid-state reactions and solution method. Its crystal structure features a three-dimensional framework composed of corner-sharing YO6 octahedra and PO4 tetrahedra. Although it is isostructural to the known langbeinite-type sulfate K2Zn2(SO4)3, 1 exhibits a sharply enhanced NLO effect (about 3 times that of K2Zn2(SO4)3). On the basis of structural analysis and theory calculations, the improved performance of compound 1 is mainly ascribed to the aliovalent replacement of ZnO6 by YO6 octahedra. Our studies indicated that it may be an effective method to develop non-centrosymmetric compounds by aliovalent substitution. By aliovalent-substituted synthesis method based on K2Zn2(SO4)3, a new phosphate LiRb2Y2(PO4)3 was synthesized and exhibits a sharply enhanced second-harmonic generation (SHG) effect. [Display omitted]