Search

Borate crystals can be chemically and functionally modified by the fluorination strategy, which encourages the identification of emerging fluorooxoborates with a structure and set of characteristics not seen in any other oxide parents. However, the bulk of fluorooxoborates have been found accidentally, rational methods of synthesis are required, particularly for the infrequently occurring poly‐fluorinated components. Herein, we reported the use of bifluoride salts as a potent source of fluorine to prepare fluorooxoborates that contain rarely tri‐fluorinated [BF3X] (X=O and CH3) tetrahedra and eleven compounds were found. We identified the optical properties of the organofluorinated group [CH3BF3] and their potential for nonlinear optics for the first time. Among these, two non‐centrosymmetric components hold potential for the production of 266 nm harmonic coherent light for nonlinear optics, and more crucially, have the benefit of growing large size single crystals. Our study establishes experimental conditions for the coexistence of the diverse functional groups, enabling the production of poly‐fluorinated optical crystals. [ABSTRACT FROM AUTHOR]

Polarization modulation of deep‐UV light is of significance to current technologies, and to this end, the birefringent crystal has emerged as an invaluable material as it allows for effective light modulation. Herein, a double‐modification strategy driven by F and OH anions that makes double effects towards the critical property enhancement of deep‐UV birefringent crystals is proposed. This leads to a new hydroxyborate (NH4)4[B12O16F4(OH)4] with giant cluster as a deep‐UV birefringent crystal with large birefringence (Δnexp.=0.12@546.1 nm). This birefringence is a record among inorganic hydroxyborates with experimentally measured birefringence. Structural analysis shows that the near‐plane arrangement of [B12O16F4(OH)4] cluster is responsible for the large optical anisotropy. Theoretical calculations indicate that its π‐conjugated [BO3] and [BO2OH] units are the main source of this large optical anisotropy. [ABSTRACT FROM AUTHOR]

Discovery of new efficient nonlinear optical (NLO) materials with large second‐order nonlinearity for the short‐wave ultraviolet spectral region (λPM≤266 nm, PM=phase‐matching) is still very challenging. Herein, a new beryllium‐free borate CaZn2(BO3)2 with Sr2Be2B2O7 (SBBO) double‐layered like configuration was rationally designed, which not only preserves the structural merits but also eliminates the limitations of the SBBO crystal. CaZn2(BO3)2 shows a large PM second harmonic generation (SHG) reponse of 3.8×KDP, which is 38 times higher than that of its barium analogue. This enhancement mainly originates from the 1[Zn2O6]∞ polar chains with a large net dipole moment and [BO3] units with a high NLO active density. Our findings show the great significance of the [ZnO4] tetrahedra introduced strategy to design beryllium‐free SBBO‐type NLO crystals and also verify the feasibility of using simple non‐isomorphic substitution to induce giant second‐order nonlinearity enhancement. [ABSTRACT FROM AUTHOR]

Discovery of new efficient nonlinear optical (NLO) materials with large second‐order nonlinearity for the short‐wave ultraviolet spectral region (λPM≤266 nm, PM=phase‐matching) is still very challenging. Herein, a new beryllium‐free borate CaZn2(BO3)2 with Sr2Be2B2O7 (SBBO) double‐layered like configuration was rationally designed, which not only preserves the structural merits but also eliminates the limitations of the SBBO crystal. CaZn2(BO3)2 shows a large PM second harmonic generation (SHG) reponse of 3.8×KDP, which is 38 times higher than that of its barium analogue. This enhancement mainly originates from the 1[Zn2O6]∞ polar chains with a large net dipole moment and [BO3] units with a high NLO active density. Our findings show the great significance of the [ZnO4] tetrahedra introduced strategy to design beryllium‐free SBBO‐type NLO crystals and also verify the feasibility of using simple non‐isomorphic substitution to induce giant second‐order nonlinearity enhancement. [ABSTRACT FROM AUTHOR]

The design and preparation of new birefringent materials with large birefringence, especially those for the short-wavelength spectral region, are still active since they play an important role in creating polarized light. Herein, a new organic–inorganic hybrid fluorooxoborate [C3N6H7]2[B3O3F4(OH)] was discovered following the strategy of combining two birefringence-active units to increase the optical anisotropy. The large birefringence (0.440@546 nm) and short absorption edge (240 nm) make [C3N6H7]2[B3O3F4(OH)] a potential short-wavelength ultraviolet birefringent crystal. Both the [C3N6H7] cation and [B3O3F4(OH)] anion in [C3N6H7]2[B3O3F4(OH)] are identified as birefringence-active units that induce large optical anisotropy, as evidenced by additional theoretical calculations. [ABSTRACT FROM AUTHOR]

Although phosphates are a rich source of deep-ultraviolet optical materials, the realization of large optical anisotropy in them still remains a challenge because of the small polarizability anisotropy of [PO4] units. Inspired by the fluoridation strategy and hydrogen bond interaction, a new metal-free monofluorophosphate, (N2H6)[HPO3F]2, was synthesized, which exhibits a large birefringence (cal. 0.077) and wide band gap (∼6.51 eV). Such a large birefringence in (N2H6)[HPO3F]2 sets a new record among available fluorophosphates, and the [HPO3F] unit is theoretically confirmed to be a new birefringence-active unit. [ABSTRACT FROM AUTHOR]