A2BiI5O15 (A = K+ or Rb+): two new promising nonlinear optical materials containing [I3O9]3− bridging anionic groups

Abstract

Two new alkali metal bismuth iodates, K₂BiI₅O₁₅ and Rb₂BiI₅O₁₅, have been synthesized by a hydrothermal method. They are isostructural with the same noncentrosymmetric (NCS) orthorhombic space group Abm2 and contain a unique [I₃O₉]³⁻ bridging anionic group. Their powders showed phase-matchable second-harmonic generation (SHG) effects 3 times that of KH₂PO₄ (KDP) and the laser-induced damage threshold values of 84 and 72 MW cm⁻², respectively. They also exhibit a wide transparent range (up to 12 μm) and good thermal stability (450 °C).