Chemical substitution – oriented design of a new polar PbFIO3 achieving a balance between large second-harmonic generation response and wide band gap

Abstract A new polar iodate fluoride, PbFIO3, was designed via multisite substitution by taking BiO(IO3) as a prototype. It crystalizes in the polar space group Iba2. Similar to BiO(IO3), it has an Aurivillius-type cationic [PbF]+ layer. As regarding IO3 polyhedron in PbFIO3, they inherit the beneficial arrangement of IO3 polyhedron in BiO(IO3), which result in the strong second-harmonic generation (SHG) response about 8 times that of KH2PO4 (KDP). In addition, benefiting from the introduction of strong electronegative F atoms replacing the O atoms of 2D (Bi2O2)2+ layer, PbFIO3 exhibits a larger band gap about 3.87 eV compared to BiO(IO3) (3.3 eV). Besides strong SHG response and wide band gap, PbFIO3 possess a moderate birefringence of 0.06@546.1 nm as well. These superior linear and nonlinear optical (NLO) properties make PbFIO3 being a potential NLO crystal.