Angewandte Chemie · 2018 · 115 citations · 49 references
Natural SciencesChemistryMaterials ScienceCrystal StructureMaterials ChemistryOptical MaterialsCrystal SystemsMolecular SymmetryNonlinear Optical MaterialsNonlinear OpticsOptical Properties Of SolidsPhotonic MaterialsAnisotropyBand GapChromophore DesignChromophore StructureNonlinear Optical PropertiesOptical Band GapOptical PropertiesRational Design
Fluorooxoborates, with large band gaps, high anisotropy, and non‑centrosymmetric structures enabled by polarized [BOxFx] units, are promising for UV and deep‑UV nonlinear optical materials. The study reports the first asymmetric alkaline‑earth metal fluorooxoborate SrB₅O₇F₃, designed by adapting the classic Sr₂Be₂B₂O₇ structure. The crystal was rationally designed by modifying the Sr₂Be₂B₂O₇ framework and its covalent B–F bonds were confirmed by solid‑state ¹⁹F and ¹¹B MAS‑NMR spectroscopy. SrB₅O₇F₃ contains a novel near‑planar [B₅O₉F₃]⁶⁻ building block and exhibits optical properties suitable for deep‑UV nonlinear optics, enabling direct second‑harmonic generation.
Abstract Fluorooxoborates, benefiting from the large optical band gap, high anisotropy, and ever‐greater possibility to form non‐centrosymmetric structures activated by the large polarization of [BO x F 4− x ] ( x +1)− building blocks, have been considered as the new fertile fields for searching the ultraviolet (UV) and deep‐UV nonlinear optical (NLO) materials. Herein, we report the first asymmetric alkaline‐earth metal fluorooxoborate SrB 5 O 7 F 3 , which is rationally designed by taking the classic Sr 2 Be 2 B 2 O 7 (SBBO) as a maternal structure. Its [B 5 O 9 F 3 ] 6− fundamental building block with near‐planar configuration composed by two edge‐sharing [B 3 O 6 F 2 ] 5− rings in SrB 5 O 7 F 3 has not been reported in any other borates. Solid state 19 F and 11 B magic‐angle spinning NMR spectroscopy verifies the presence of covalent B−F bonds in SrB 5 O 7 F 3 . Property characterizations reveal that SrB 5 O 7 F 3 possesses the optical properties required for deep‐UV NLO applications, which make SrB 5 O 7 F 3 a promising crystal that could produce deep‐UV coherent light by the direct SHG process.
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Design and synthesis of an ultraviolet-transparent nonlinear optical crystal Sr2Be2B2O7
Chuangtian Chen, Yebin Wang, Baichang Wu et al. · Nature · 1995 · 985 citations