CsBP2O6(OH)2: a second-order NLO material with a unique borophosphate anionic partial structure and strong SHG effect

Abstract

A noncentrosymmetric (NCS) alkali-metal borophosphate CsBP₂O₆(OH)₂ (CBPO) containing a unique borophosphate anionic partial structure has been obtained through a mixed-solvent thermal method. Its structure could be regarded as a 1-D chain that is built by Cs⁺ cations and a unique anionic chain [BP₂O₆(OH)₂]_∞ⁿ⁻ composed of BO₄ and PO₃(OH) groups. CBPO possesses a wide UV-vis transparent range and shows a strong SHG response. Moreover, we have well explored and established the origin of the SHG effect by dipole moment and PDOS calculations. This work will help inspire and stimulate scientists to discover more such excellent NLO materials.