KB(PO₄)F: a novel acentric deep-ultraviolet material

Area of Science:

• Materials Science
• Optics
• Crystallography

Background:

• Potassium beryllium fluoroborate (KBBF) is a leading deep-ultraviolet nonlinear optical (NLO) material.
• KBBF growth is limited by small crystal sizes and the use of toxic beryllium.
• There is a need for new, safer, and more scalable deep-ultraviolet NLO materials.

Purpose of the Study:

• To discover and characterize a novel deep-ultraviolet NLO material.
• To address the limitations of KBBF regarding crystal size and elemental toxicity.
• To explore alternative materials for advanced optical applications.

Main Methods:

• Synthesis and crystal growth of potassium fluorinated borophosphate (KBPF).
• Characterization using powder X-ray diffraction (PXRD), SEM, TG-DSC, FTIR, and UV-Vis-NIR diffuse reflectance.
• Second-harmonic generation (SHG) analysis and single-crystal X-ray structure refinement.
• First-principles calculations using density functional theory (DFT) for optical property evaluation.

Main Results:

• Discovery of a novel anhydrous non-centrosymmetric alkali fluorinated borophosphate, KBPF.
• KBPF exhibits a cut-off wavelength below 200 nm and a significant SHG effect.
• KBPF crystals can be grown using cost-effective methods and show no detectable hygroscopicity.
• Stronger interlayer bonds in KBPF facilitate the growth of larger crystals compared to KBBF.

Conclusions:

• KBPF is a promising new deep-ultraviolet NLO material with advantages over KBBF.
• The material's composition from common elements and cost-effective synthesis offer scalability.
• KBPF's properties make it suitable for applications requiring deep-ultraviolet nonlinear optics.