ZrF₂(IO₃)₂ and RbGaF₃(IO₃): Two Promising Birefringent Crystals Featuring 1D Metal-Fluoride Cationic Chains and Wide Bandgaps

Abstract

Herein, two novel metal iodate-fluorides, ZrF 2 (IO 3 ) 2 and RbGaF 3 (IO 3 ), have been prepared via hydrothermal reactions. In the structure of ZrF 2 (IO 3 ) 2 , neighboring Zr atoms are connected via a pair of F atoms into the one-dimensional (1D) [ZrF 2 ] 2+ cationic chain, which further attaches two iodate groups forming 1D ZrF 2 (IO 3 ) 2 , whereas the 1D cationic chain in RbGaF 3 (IO 3 ) is [GaF] 2+ , formatted by the bridging of Ga 3+ cations and axial F − anions, which further connect with one iodate group and two terminal F − anions into 1D [GaF 3 (IO 3 )] − anionic chains. According to the experimental characterization and theoretical calculations, both of them exhibit wide bandgaps (4.24 and 4.61 eV), short absorption edges (242 and 216 nm), and large birefringence (Δn cal = 0.329 @1064 nm and Δn cal = 0.174 @1064 nm for ZrF 2 (IO 3 ) 2 and RbGaF 3 (IO 3 ), respectively), indicating that they can be candidates as UV birefringent materials.

Four UV Transparent Linear and Nonlinear Optical Materials Explored from Pure Selenite Compounds

“…Through the investigation of UV NLO selenite materials, we found that the bandgap of Pb 2 GaF 2 (SeO 3 ) 2 Cl was increased to 4.32 eV by replacing V 5+ in the parent compound Pb 2 VO 2 (SeO 3 ) 2 Cl (2.41 eV) with Ga 3+ . [40,41] Recent reports on Al 3+ /Ga 3+ -containing compounds, such as NaAl(Te 4 O 10 ) (4.02 eV, 0.128@1064 nm), [42] K 2 Ga 2 (HTe 6 O 16 )(HTeO 3 ) (4.01 eV, 0.089@1064 nm), [42] Ga 2 (TeO 3 )(SO 4 )(OH) 2 (4.23 eV, 0.103@1064 nm), [43] Nd 3 [Ga 3 O 3 S 3 ][Ge 2 O 7 ] (4.35 eV, 0.094@1064 nm), [44] and RbGaF 3 (IO 3 ) (4.61 eV, 0.174@1064 nm), [45] have displayed large birefringence and wide bandgap simultaneously. It can be seen that Al 3+ /Ga 3+ are the suitable cations for designing UV pure selenite.…”

From H12C4N2CdI4 to H11C4N2CdI3: a highly polarizable CdNI3 tetrahedron induced a sharp enhancement of second harmonic generation response and birefringence

“…[28][29][30][31][32][33][34] However, on the one hand, the use of SCLAP cations is known to cause red shis in absorption edges and reduce bandgaps of the resulting crystals, limiting their potential applications in the ultraviolet (UV) and deep-UV regions. [35][36][37][38][39][40] For instance, Mao's group recently reported a series of Ge 2+ -containing OIMHs, in which (CH 3 NH 3 )GeBr 3 shows a large SHG response (5. 44 and ((CH 3 ) 3 NCH 2 Cl)CdCl 3 , 46 usually possess wide bandgaps (>5.0 eV) but relatively weak SHG effects (<1.0 × KDP).…”

AAl(Te4O10) (A = Na, Ag) and K2Ga2(HTe6O16)(HTeO3): Three Aluminum/Gallium Tellurites with Large Birefringence and Wide Band Gap

“…45−48 Some compounds containing Ga 3+ have been reported to have large birefringence and wide band gap. 49 For example, the birefringence values of Nd 3 [Ga 3 O 3 S 3 ][Ge 2 O 7 ] (4.35 eV), 50 LiGaF 2 (IO 3 ) 2 (4.33 eV), 51 RbGaF 3 (IO 3 ) (4.61 eV), 52 and Ga 2 (TeO 3 )(SO 4 )(OH) 2 (4.23 eV) 23 at 1064 nm can reach 0.094, 0.181, 0.174, and 0.103, respectively. To obtain wideband-gap tellurite birefringent materials, we focused our energy on gallium/aluminum tellurite systems.…”

“…It is reported that when group IIIA metals, such as Al 3+ and Ga 3+ , replace the d 0 transition metals, the absorption edge of the materials will blue shift into the ultraviolet (UV) region of the spectrum due to the prohibited d–d transitions. − Some compounds containing Ga 3+ have been reported to have large birefringence and wide band gap . For example, the birefringence values of Nd 3 [Ga 3 O 3 S 3 ]­[Ge 2 O 7 ] (4.35 eV), LiGaF 2 (IO 3 ) 2 (4.33 eV), RbGaF 3 (IO 3 ) (4.61 eV), and Ga 2 (TeO 3 )­(SO 4 )­(OH) 2 (4.23 eV) at 1064 nm can reach 0.094, 0.181, 0.174, and 0.103, respectively. To obtain wide-band-gap tellurite birefringent materials, we focused our energy on gallium/aluminum tellurite systems.…”