- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Exploration of new birefringent crystals in bismuth d0 transition metal selenites
摘要： The first examples of bismuth fluoride selenites with d0-TM/Te(VI) polyhedrons, namely, Bi4TiO2F4(SeO3)4 (1), Bi4NbO3F3(SeO3)4 (2), Bi4TeO4F2(TeO3)2(SeO3)2 (3), Bi2F2(MoO4)(SeO3) (4) and Bi2ZrO2F2(SeO3)2 (5) have been successfully synthesized under hydrothermal reactions by aliovalent substitution. The five new compounds feature three different types of structures. Compounds 1-3, containing Ti(IV), Nb(V) and Te(VI) respectively, are isostructural, exhibiting a new 3D framework composed of 3D bismuth oxyfluoride architecture with intersecting tunnels occupied by d0-TM/Te(VI) octahedrons and selenite/tellurite groups. Compound Bi4TeO4F2(TeO3)2(SeO3)2 (3) is the first structure containing Se(IV) and mixed-valent Te(IV)/Te(VI) cations simultaneously. Compound 4 features a new 3D structure formed by 3D bismuth oxyfluoride network with MoO4 tetrahedrons and selenites groups embeded in the 1D tunnels. Compound 5 displays a novel pillar-layered 3D open framework consisted of 2D bismuth oxide layers bridged by the [ZrO2F2(SeO3)2]6- polyanions. Theoretical calculations revealed that the five compounds displayed very strong birefringence. The birefringence values of compounds 1-3, especially, are above 0.19 at 1064 nm, which are bigger than the mineral calcite. Based on the structure and property analysis, we found that the asymmetric SeO3 groups (and TeO3 in compound 3) displayed the largest anisotropy compared with the bismuth cations and the d0 TM/Te polyhedrons, which is beneficial to the birefringence.
关键词： metal selenites,d0 transition metals,aliovalent substitution,hydrothermal reactions,birefringent crystals
更新于2025-09-23 15:23:52
-
A Facile Route for NLO Materials: Three-Site Alivolent Substitution Involving One Cation and Two Anions
摘要： Two mixed-metal gallium iodate fluorides, namely, α- and β-Ba2[GaF4(IO3)2](IO3) (1 and 2) have been obtained by the aliovalent substitutions of α- and β-Ba2[VO2F2(IO3)2](IO3) (3 and 4) involving one cationic and two anionic sites. Both of them display large SHG signals (~6 × KDP), large energy bandgaps (4.61 and 4.35 eV), wide transmittance ranges (~0.27-12.5 μm), and large relevant LDTs (29.7 × and 28.3 × AgGaS2, respectively), which indicates that 1 and 2 are potential second-order NLO materials in ultraviolet to mid-infrared. Our studies propose that three-site aliovalent substitution is a facile route for the discovery of good NLO materials.
关键词： aliovalent substitution,hydrothermal synthesis,NLO material,mixed-metal iodate fluoride,theoretical calculations
更新于2025-09-23 15:23:52
-
Pb <sub/>2</sub> GaF <sub/>2</sub> (SeO <sub/>3</sub> ) <sub/>2</sub> Cl: Band Engineering Strategy by Aliovalent Substitution for Enlarging Bandgap while Keeping Strong Second Harmonic Generation Response
摘要： Wide bandgap and strong second-order generation (SHG) effect are two crucial but contradictory conditions for practical nonlinear optical (NLO) materials. Herein, a new NLO crystal Pb2GaF2(SeO3)2Cl (I) containing novel functional (GaO3F3)6? octahedra is designed and synthesized by a rational band engineering strategy with aliovalent substitution. Benefiting from the removal of transition metal cations and the introduction of bridged F anions, I exhibits the widest bandgap among all reported phase-matchable NLO selenites. Meanwhile, a strong SHG response more than 4.5 times of KH2PO4 (KDP) is maintained. The dominate role of the (GaO3F3)6? groups to the enlarged bandgap in I are elucidated by first-principles studies.
关键词： aliovalent substitution,second harmonic generation,nonlinear optical materials,selenites,band engineering
更新于2025-09-23 15:21:21