Coexistence of Strong Second Harmonic Generation Response and Wide Band Gap in AZn₄Ga₅S₁₂ (A=K, Rb, Cs) with 3D Diamond‐like Frameworks

Abstract

Mid-infrared (MIR, 2-20 μm) second-order nonlinear optical (NLO) materials with outstanding performances are of great importance in laser science and technology. However, the enormous challenge to design and synthesize an excellent MIR NLO material lies in achieving simultaneously a strong second harmonic generation (SHG) response [d >0.6 × AgGaS (AGS)] and wide band gap (E >3.5 eV). Herein three new MIR NLO materials, AZn Ga S (A=K, Rb, Cs) are reported, which crystallize in the KCd Ga S -type structure and adopt a 3D diamond-like framework (DLF) consisting of MS (M=Zn/Ga) tetrahedra; achieving the desired balance with strong powder SHG response (1.2-1.4 × AGS) and wide band gap (E ≈3.65 eV). Moreover, they also show large laser induced damage thresholds (LIDTs, 36 × AGS), a wide range of optical transparency (0.4-25 μm) and ultrahigh thermal stability (up to 1400 K). Upon analyzing the structure-property relationship of AX X Q family, these 3D DLF structures can be used as a highly versatile and tunable platform for designing excellent MIR NLO materials.

A2SrMIVS4 (A = Li, Na; MIV = Ge, Sn) concurrently exhibiting wide bandgaps and good nonlinear optical responses as new potential infrared nonlinear optical materials

“…4a and b). The above results also indicate that the cosubstitution of alkali or alkaline earth metals in the same main group has little influence on the material E g , which can also be confirmed in relative systems including AZn 4 Ga 5 S 12 (A = K, Rb, Cs; ∼3.65 eV)19 and A 3 Ga 3 PS 8 Cl (A = K, Rb; 3.60 vs. 3.65 eV) 10 d . Besides, their shortwave absorption edges are lower than 400 nm and such a low absorption edge can remove the effect of harmful TPA at 1 μm for another classical ZnGeP 2 ; thus, recent mature laser sources ( e.g.…”

Salt-Inclusion Chalcogenide [Ba4Cl2][ZnGa4S10]: Rational Design of an IR Nonlinear Optical Material with Superior Comprehensive Performance Derived from AgGaS2

“…3a, the UV−vis−NIR diffuse reflectance spectrum based on the polycrystalline powder sample demonstrates the optical E g of 3.85 eV for [Ba 4 Cl 2 ]-[ZnGa 4 S 10 ], which is not only much wider than that of prototype AGS (2.56 eV) 42,43 but also larger than those of the previously reported AZn 4 Ga 5 S 12 (A = K, Rb, and Cs; E g = 3.65 eV) obtained by single cation substitution. 44 Moreover, the transmission spectrum measurements indicate that [Ba 4 Cl 2 ]-[ZnGa 4 S 10 ] possesses a broad transparency region from 0.29 (UV−vis range) to 13.7 μm (IR range), as shown in Figure 3b. Such data are better than that of AGS (0.48−11.4 μm) 45 and can run cross the two vital atmospheric transparency windows (3−5 and 8−12 μm).…”

LiGa2PS6 and LiCd3PS6: Molecular Designs of Two New Mid-Infrared Nonlinear Optical Materials

“…Recently, our efforts to introduce the PS 4 tetrahedron into AgGaS 2 led to the discovery of AgGa 2 PS 6 , which displays both large SHG response and high LDT, in addition to the low T m . 30 The use of more electropositive elements than Ag, such as alkali or alkali earth metal as cations in the chalcogenide-based NLO materials, can greatly increase the E g values, as exemplified by LiGaS 2 (4.2 eV) 31 versus AgGaS 2 (2.6 eV), 8 as well as Li 2 ZnSiS 4 (3.9 eV), 32 Li 2 BaGeS 4 (3.7 eV), 33 Na 2 BaGeS 4 (3.7 eV), 34 KZn 4 Ge 5 S 12 (3.7 eV), 35 BaGa 4 S 7 (3.5 eV), 36 Na 2 ZnGe 2 S 6 (3.3 eV), 37 etc. In this work, lithium is used to replace the silver in AgGa 2 PS 6 , which led to LiGa 2 PS 6 with an enlarged E g (3.15 eV) and suitable Δn (0.08), but slightly decreased SHG effect.…”