K₂ZnSn₃Se₈: A Non‐Centrosymmetric Zinc Selenidostannate(IV) Featuring Interesting Covalently Bonded [ZnSn₃Se₈]²⁻ Layer and Exhibiting Intriguing Second Harmonic Generation Activity

Abstract

Non-centrosymmetric zinc selenidostannate(IV) K ZnSn Se was synthesized. It features interesting covalently bonded [ZnSn Se ] layers with K cations filling in the interlayer voids. The phonon spectrum was calculated to clarify its structural stability. Based on the X-ray diffraction data along with the Raman spectrum, the major bonding features of the title compound were identified. According to the UV/vis-NIR spectroscopy, K ZnSn Se possesses a typical direct band gap of 2.10 eV, which is in good agreement with the band structure calculations. Moreover, our experimental measurements and detailed theoretical calculations reveal that K ZnSn Se is a new phase-matchable nonlinear optical material with a powder second harmonic generation (SHG) signal about 0.6 times of that of AgGaS .

Centrosymmetric or Noncentrosymmetric? Transition Metals Talking in K2TGe3S8(T = Co, Fe)

“…4) space group as confirmed by the second harmonic generation (SHG) response. K 2 FeGe 3 S 8 belongs to the well-known A 2 M II M Iv 3 Q 8 (A = alkali metals, M II =divalent transition metals, M IV = Ge or Sn, Q = S or Se) system, which mainly features a layered crystal structure. − K 2 CoGe 3 S 8 forms in a new structure type with a centrosymmetric P (no. 2) space group.…”

Triclinic Layered A2ZnSi3S8 (A = Rb and Cs) with Large Optical Anisotropy and Systematic Research on the Inherent Structure–Performance Relationship in the A2MIIBMIV3Q8 Family

“…Surveying the crystal structures in the 2–1–3–8 A 2 M II M IV 3 Q 8 system, − they crystallize in the five different space groups: triclinic P 1̅, monoclinic ( P 2 1 and P 2 1 / n ), orthorhombic P 2 1 2 1 2 1 , and cubic Pa 3̅. Among these, Zn and Sn atoms are occupied in one site with Zn/Sn = 0.25:0.75 in the structure of high-symmetry β-K 2 ZnSn 3 S 8 (cubic Pa 3̅), which is different with the fully occupied sites of Group 12 and Group 14 atoms in low-symmetrical compounds (from orthorhombic to triclinic) (Figure ).…”

“…Inorganic functional materials have been attracted many attentions in various application fields because of their multiple crystal structures and flexible physicochemical properties. − As for chalcogenides, survey on their structures shows that they have the different dimensionalities from zero-dimensional (0D) to 3D network through the chemical substitution, and many systems have been discovered so far, for example, A-M II 4 -M IIIA 5 -Q 12 (A = K, Rb, and Cs; II = Zn, Cd, Hg, and Mn; IIIA = Ga, and In; Q = chalcogen) compounds have shown superior second harmonic generation (SHG) responses, fluorescence emission, and magnetic properties as potential multifunctional materials. − Other famous research systems include the diamondlike semiconductors I 2 -II-IV-Q 4 (DLSs), , AE-I 2 -IV-Q 4 (AE = Sr and Ba; I = Li, Ag, Cu, and Na; IV = Si, Ge, and Sn; Q = chalcogen), − and the RE 3 -M-M′-Q 7 P6 3 family, − and so on. Another important family is the A 2 M II M IV 3 Q 8 family (2–1–3–8 system: A = monovalent alkali metal; M II = divalent transition metals; M IV = group 14 metals; Q = chalcogen). − In the above 2–1–3–8 system, many compounds were discovered and they crystallize in the various space groups, such as P 1̅, P 2 1 , P 2 1 / n , P 2 1 2 1 2 1 and cubic Pa 3̅. For instance, K 2 ZnSn 3 S 8 compounds exhibit a phase-change behavior (α: P 1̅ vs β: Pa 3̅) that is also viewed as the only one discovered polymorph in this 2–1–3–8 system; K 2 FeGe 3 Se 8 and K 2 MnGe 3 S 8 show the potential magnetic performances with interesting antiferromagnetic transition at ∼10 and 8.1 K, respectively. , Besides, several of noncentrosymmetrical (NCS) P 2 1 compounds (K 2 ZnSn 3 Se 8 , K 2 ZnGe 3 S 8 , and K 2 MnGe 3 S 8 ) exhibit the considerable powder SHG responses based on experimental evaluation; − Cs 2 HgSn 3 Se 8 crystal possesses the strong photoconductivity effect ((μτ) h|| = 7.78 × 10 –5 cm 2 /V) .…”

“…Another important family is the A 2 M II M IV 3 Q 8 family (2–1–3–8 system: A = monovalent alkali metal; M II = divalent transition metals; M IV = group 14 metals; Q = chalcogen). − In the above 2–1–3–8 system, many compounds were discovered and they crystallize in the various space groups, such as P 1̅, P 2 1 , P 2 1 / n , P 2 1 2 1 2 1 and cubic Pa 3̅. For instance, K 2 ZnSn 3 S 8 compounds exhibit a phase-change behavior (α: P 1̅ vs β: Pa 3̅) that is also viewed as the only one discovered polymorph in this 2–1–3–8 system; K 2 FeGe 3 Se 8 and K 2 MnGe 3 S 8 show the potential magnetic performances with interesting antiferromagnetic transition at ∼10 and 8.1 K, respectively. , Besides, several of noncentrosymmetrical (NCS) P 2 1 compounds (K 2 ZnSn 3 Se 8 , K 2 ZnGe 3 S 8 , and K 2 MnGe 3 S 8 ) exhibit the considerable powder SHG responses based on experimental evaluation; − Cs 2 HgSn 3 Se 8 crystal possesses the strong photoconductivity effect ((μτ) h|| = 7.78 × 10 –5 cm 2 /V) . Therefore, 2–1–3–8 compounds show various physicochemical properties and could be used in the multiple application fields.…”

Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16: Strong Nonlinear Optical Response in Quaternary Diamond‐Like Selenide Networks

“…Today,m aterial designs based on exploiting asymmetricb uilding units, such as distorted tetrahedra (GaS 4 ,G eS 4 ), p-conjugated trigonal planes ([HgSe 3 ] 4À ), MQ n polyhedra (M = second-order Jahn-Teller distorted d 0 and d 10 metal centers,e .g.,T a 5 + ,Z r 4 + ,C d 2 + ;Q = chalcogen), and some polar anionic groups with stereochemically active lone pairs ([AsS 3 ] 3À ,[ SbS 3 ] 3À ,[Te S 3 ] 2À ), has been enabled by broad-based advances in the understanding of synthesis and characterization methodology. [13][14][15][16][17][18][19][20][21] Furthermore, the diversity of asymmetric building units in as tructure would increase the difficulty of spontaneously producing am irror plane or inversion centerd uring the packing process,w hich in turn may promote the generation of an NCS structure, as explained by BaGa 2 MQ 6 (M = Si, Ge, Sn;Q = S, Se), Ba 23 Ga 8 Sb 2 S 38 , A 3 Ta 2 AsS 11 (A = K, Rb), ands oo n. [22][23][24][25][26][27][28] Consequently,t oo btain NCS structures with strongN LO responses, we are interested in exploring structures that contain two types of asymmetric buildingu nits.…”