Structure and Characterization of K2Na3B2P3O13, a New Nonlinear Optical Borophosphate with One-Dimensional Chain Structure and Short Ultraviolet Cutoff Edge

Wenhao Liu; Ming-Hsien Lee; Ruixin Guo; Jiyong Yao

doi:10.1021/acs.inorgchem.2c04499

Structure and Characterization of K₂Na₃B₂P₃O₁₃, a New Nonlinear Optical Borophosphate with One-Dimensional Chain Structure and Short Ultraviolet Cutoff Edge

Inorg Chem. 2023 Feb 6;62(5):2480-2488. doi: 10.1021/acs.inorgchem.2c04499. Epub 2023 Jan 25.

Authors

Wenhao Liu^{1

2

3}, Ming-Hsien Lee⁴, Ruixin Guo^{1

2}, Jiyong Yao^{1

2}

Affiliations

¹ Beijing Center for Crystal Research and Development, Key Lab of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China.
² Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
³ University of Chinese Academy of Sciences, Beijing 100049, P. R. China.
⁴ Department of Physics, Tamkang University, Tamsui, New Taipei 25137, Taiwan.

PMID: 36697214
DOI: 10.1021/acs.inorgchem.2c04499

Abstract

Nonlinear optical (NLO) crystals, being the primary medium for laser wavelength conversion, are crucial in all-solid-state lasers. Borophosphates offer more structural varieties than pure borates and phosphates, and they have become popular as NLO crystal candidates. Through spontaneous crystallization, we acquired a noncentrosymmetric alkali metal borophosphate crystal material, K₂Na₃B₂P₃O₁₃ (KNBPO). KNBPO crystallizes in the orthorhombic Cmc2₁ space group with the following unit cell parameters: a = 13.9238(18) Å, b = 6.7673(8) Å, c = 12.1298(15) Å, and Z = 4, and its structure is characterized by a fundamental building unit 1_∞ [B₂P₃O₁₃] chain structure made up of bridging oxygen linkages between BO₄ and PO₄ tetrahedra. KNBPO has a short ultraviolet (UV) cut-off edge (<186 nm), a congruent melting characteristic, good thermal stability, and a moderate second harmonic generation response roughly 0.42 times that of KH₂PO₄. Theoretical calculations reveal that the optical properties of the compound mainly originate from BO₄ and PO₄ units. Due to the short UV cut-off edge, KNBPO can be used as a potential NLO material in the UV and even deep UV regions, and it enhances the structural variety of borophosphates, which has a reference value for scholars investigating similar materials.