Ultraviolet nonlinear optical crystal: (NH4)ZnPO4

Abstract

Ultraviolet (UV) nonlinear-optical (NLO) material has significant application in many domains. From the point of fundamental research and practical application, it is important for expanding the scope of UV NLO material and establishing new synthetic methodology. As a promising candidate, inorganic metal phosphate has gained numerous attentions of researchers in the hunt for excellent UV NLO material. Previous studies have demonstrated that the introduction of alkali-metal (or alkali-earth-metal) with large radii, transition metal bearing d10 electron configuration into phosphate system could give birth to superior UV NLO material. Considering the charge and size similarity of ammonium (NH4+) and alkali-metal potassium element (K+), we attempted to fabricate d10 metal phosphate templated by NH4+ to search for potential UV NLO material. Through the assembly of NH4+, Zn2+ and phosphate, an inorganic metal phosphate (NH4)ZnPO4 (1) has been synthesized. Compound 1 exhibits acentric three-dimentional (3D) anionic inorganic frame with NH4+ as counter-ion. The second-harmonic-generation (SHG) efficiency of 1 is comparable to the commercialized KH2PO4 (KDP). Our work offers a new path for the design of UV NLO material by introducing transition metal with d10 electron configuration and ammonium into phosphate system.