EuSi₇P₁₀: An Inorganic Supramolecular Nonlinear Optical Crystal Exhibiting Strong Second-Harmonic Generation Response

Abstract

Inorganic supramolecular compounds are the emergent class of infrared (IR) nonlinear optical (NLO) materials. However, the reported inorganic supramolecular IR NLO pnictides are still scarce. In this work, a new inorganic supramolecular IR NLO phosphide, EuSi 7 P 10 , has been synthesized using the metal salt flux method. The structure of EuSi 7 P 10 features an anionic host framework containing the oriented [Si 7 P 16 ] dual-T2 supertetrahedra with the guest Eu 2+ cations filling in the intervals. Additionally, EuSi 7 P 10 exhibits strong phase-matched (PM) second-harmonic generation (SHG) (4.0 × AgGaS 2 ), large birefringence (0.087 @ 2050 nm), and wide infrared transparency. This study highlights the potential of inorganic supramolecular pnictides for exploring high-performance IR NLO crystals.