From AgGaS₂to AgHgPS₄: vacancy defects and highly distorted HgS₄tetrahedra double-induced remarkable second-harmonic generation response

Abstract

Great enhancement of the second harmonic generation response is achieved in AgHgPS4 by introducing vacancy defects and highly distorted HgS4 tetrahedra using AgGaS2 as the template.

Structural Modulation from Cu3PS4 to Cu5Zn0.5P2S8: Single-Site Aliovalent-Substitution-Driven Second-Harmonic-Generation Enhancement

“…In terms of the way of anion accumulation, the 3D DL structure of Cu 5 Zn 0.5 P 2 S 8 can be seen as an arrangement of sulfur atoms in a hexagonal close packed arrangement of sulfur layers stacked perpendicular to ab plane (Figure d). As given in Table S3, the M(1), Cu(2) and P atoms are tetrahedral coordination, and the bond lengths of M(1)–S, Cu(2)–S, and P–S lie in the ranges of 2.285(2)–2.312(2) Å, 2.303(3)–2.368(3) Å, and 2.055(4)–2.071(3) Å, respectively, which are similar to the situation reported in other DL chalcophosphates. − …”

“…There are some remarkable examples such as AgZnPS 4 (E g = 2.76 eV; d ij = 1.8AgGaS 2 ), 15 CuZnPS 4 (E g = 3.0 eV; d ij = 3AgGaS 2 ), 16 HgCuPS 4 (E g = 2.03 eV; d ij = 6.5AgGaS 2 ), 17 and HgAgPS 4 (E g = 2.63 eV; d ij = 5.1AgGaS 2 ). 18 Compared with the quaternary system, ternary thiophosphates with DL structure are rarely reported, and the known examples only existed in InPS 4 (E g = 3.12 eV; d 36 = 14 pm/V), 19 Zn 3 P 2 S 8 (E g = 3.12 eV; d ij = 2.6AgGaS 2 ), 20 and Sn 2 P 2 S 6 (E g = 2.34 eV; d 11 = 12 pm/ V). 21,22 In the meantime, ternary Cu 3 PS 4 came into our sights, and it was thought to perform well by theoretical studies (d 33 = 21 pm/V), but no relevant experimental reports of its NLO performance were published.…”

“…In recent decades, plenty of noncentrosymmetric (NCS) chalcophosphates have been discovered as favorable candidates for IR-NLO applications because they can achieve many crucial conditions for promising IR-NLO crystals, such as a wide band gap ( E g ), large SHG effect ( d ij ), high LIDT, and low melting point. , Among these, thiophosphates with diamond-like (DL) structure are hotly discussed because the intrinsic advantage of the crystal structure can be a very noticeable contribution to the NLO performance. There are some remarkable examples such as AgZnPS 4 ( E g = 2.76 eV; d ij = 1.8AgGaS 2 ), CuZnPS 4 ( E g = 3.0 eV; d ij = 3AgGaS 2 ), HgCuPS 4 ( E g = 2.03 eV; d ij = 6.5AgGaS 2 ), and HgAgPS 4 ( E g = 2.63 eV; d ij = 5.1AgGaS 2 ) . Compared with the quaternary system, ternary thiophosphates with DL structure are rarely reported, and the known examples only existed in InPS 4 ( E g = 3.12 eV; d 36 = 14 pm/V), Zn 3 P 2 S 8 ( E g = 3.12 eV; d ij = 2.6AgGaS 2 ), and Sn 2 P 2 S 6 ( E g = 2.34 eV; d 11 = 12 pm/V). , In the meantime, ternary Cu 3 PS 4 came into our sights, and it was thought to perform well by theoretical studies ( d 33 = 21 pm/V), but no relevant experimental reports of its NLO performance were published .…”

Structural modification from centrosymmetric Rb4Hg2Ge2S8 to noncentrosymmetric (Na3Rb)Hg2Ge2S8: mixed alkali metals strategy for infrared nonlinear optical material design

“…It is found that the structure of (Na 3 Rb)Hg 2 Ge 2 S 8 is composed of the typical [HgS 4 ] tetrahedron with d (Hg–S) = 2.460(13)–2.641(13) Å and the [GeS 4 ] tetrahedron with d (Ge–S) = 2.192(15)–2.237(14) Å, which are in accordance with those of related compounds. 55,56 Interestingly, each [HgS 4 ] tetrahedron is coordinated with four [GeS 4 ] tetrahedra, and each [GeS 4 ] tetrahedron is also coordinated with four [HgS 4 ] tetrahedra, which are alternately connected via corner-sharing forming a three-dimensional (3D) covalent framework structure [HgGeS 4 ] 2− , as shown in Fig. S2 (ESI†).…”

AXHg3P2S8 (A = Rb, Cs; X = Cl, Br): New Excellent Infrared Nonlinear Optical Materials with Mixed‐Anion Chalcohalide Groups of Trigonal Planar [HgS2X]3− and Tetrahedral [HgS3X]5−

“…Among the various IR NLO‐active anionic groups, Hg‐based BBUs are very competitive due to several advantages: 1) Hg 2+ cation possesses highly polarizable and deformable electron cloud, which would significantly increase the second harmonic generation (SHG) effect and birefringence; [ 12 ] 2) multiple coordination modes of Hg exist including linear, trigonal‐planar, and tetrahedral geometries, which provide opportunities to construct novel structures. Many Hg‐based IR NLO crystals have been discovered recently in both halides and chalcogenides systems with strong SHG responses and wide bandgaps ( E g ), such as Na 2 Hg 3 Ge 2 S 8 (2.2 × AGS; 2.68 eV), [ 13 ] BaHgSe 2 (1.5 × AGS; 1.56 eV), [ 14 ] SrHgGeSe 4 (4.8 × AGS; 2.42 eV), [ 15 ] CuHgPS 4 (6.5 × AGS; 2.03 eV), [ 16 ] AgHgPS 4 (5.06 × AGS, 2.63 eV), [ 17 ] Cs 2 HgI 2 Cl 2 (1 × KDP; 3.15 eV), [ 18 ] and RbHgI 3 (7 × KDP; 2.56 eV). [ 19 ] Thereby, mixed‐anion [HgQ m X n ] BBUs are expected to exist and perform well.…”