The first polyanion-substitution-driven centrosymmetric-to-noncentrosymmetric structural transformation realizing an excellent nonlinear optical supramolecule [Cd₄P₂][CdBr₄]

Abstract

The centrosymmetric-to-noncentrosymmetric structural transformation was carried out through the polyanion substitution strategy based on the [Cd5P2][SmCl6]Cl parent, offering excelent nonlinear optical material [Cd4P2][CdBr4].

KREP2S6 (RE = Sm, Gd, Tb, Dy): A Series of Polar Rare-Earth Thiophosphates with High Laser-Induced Damage Thresholds and Moderate Nonlinear-Optical Responses Synergistically Contributed by Isolated P2S6 Units and {[RE2S15]24–}∞ Layers

“…However, their intrinsic drawbacks like small laser-induced damage threshold (LIDT) or two-photon absorption restrict their applications. − Hence, exploration of IR NLO materials is still urgent and necessary. As an excellent IR NLO material, it is imperative to satisfy a series of requirements including high LIDT, large second-harmonic-generation (SHG) intensity, phase-matching (PM), etc. − Nowadays, many methods are used to develop IR NLO crystals, for example, (1) derivatives from AgGaQ 2 (Q = S, Se) like (Na 0.74 Ag 1.26 )­BaSnS 4 , Li 2 BaGeS 4 , and Na 2 Ga 3 In 3 Se 10 ; (2) normal diamond-like structures like Li 4 MgGe 2 S 7 Ag 2 In 2 SiS 3.06 Se 2.94 , and Ag 2 CdGeS 4 , in which MQ 4 (M = Ga, Ge, Cd, Zn, Si, Hg, In) tetrahedra are aligned along a special direction to generate a good NLO effect; (3) salt-inclusion chalcohalides through the host and guest parts coregulating the structures, which have achieved great success, − and (4) partial-ion-substitution-induced symmetric break from centrosymmetric (CS) to noncentrosymmetric (NCS) structures and realization of SHG activities, such as Sn 7 Br 10 S 2 , (K 0.38 Ba 0.81 )­Ga 2 Se 4 , and K 3 Ga 3 (Ge 7– x M x )­Se 20 (M = Si, Sn) …”

EuSi7P10: An Inorganic Supramolecular Nonlinear Optical Crystal Exhibiting Strong Second-Harmonic Generation Response

“…25,26 Recently, several cationic host-anionic guest pnictides have been reported as excellent IR NLO materials, such as (Hg 6 P 3 )-(In 2 Cl 9 ), (Hg 8 As 4 )(Bi 3 Cl 13 ) 16 and [Cd 4 P 2 ][CdBr 4 ]. 27 However, IR NLO pnictides with anionic host and cationic guest are still scarce.…”

“…For example, IR NLO crystals [ABa 2 Cl]­[Ga 4 S 8 ] (A = Rb, Cs) (3.30–3.35 eV, 0.9–1.0 × AGS) were designed and synthesized by replacing the Rb + guest anions in RbGaS 2 using [ClABa 2 ] 4+ polycations, the replacement of the guest components drives the transformation of crystal structure ( C 2 /c to Pmn 2 1 ) and the parallel arrangement of [Ga 4 S 8 ] 4– NLO-active layers in [ABa 2 Cl]­[Ga 4 S 8 ] (A = Rb, Cs), then leads to their excellent NLO properties. Therefore, an emerging class of inorganic supramolecular compounds, salt-inclusion chalcogenides, has been widely studied and reported as IR NLO crystals, such as [K 2 PbX]­[Ga 7 S 12 ]­(X = Cl, Br, I), K 3 Rb 3 [K 3 Cl]­[Li 2 Mn 4 Ga 12 S 27 ], Li­[LiCs 2 Cl]­[Ga 3 S 6 ], [Ba 4 Cl 2 ]­[ZnGa 4 S 10 ], [Ba 4 Cl 2 ]­[HgGa 4 S 10 ], [RbSr 3 X]­[(BS 3 ) 2 ] (X = Cl, Br). − In fact, inorganic supramolecular pnictides are more desirable to be investigated as IR NLO crystals because the SHG responses and thermal conductivities of pnictides are generally larger than those of chalcogenides. , Recently, several cationic host-anionic guest pnictides have been reported as excellent IR NLO materials, such as (Hg 6 P 3 )­(In 2 Cl 9 ), (Hg 8 As 4 )­(Bi 3 Cl 13 ) and [Cd 4 P 2 ]­[CdBr 4 ] . However, IR NLO pnictides with anionic host and cationic guest are still scarce.…”