Oxychalcogenides have become notable contenders for infrared nonlinear optical (IR NLO) applications because of their diverse heteroanionic functional motifs. However, while the main group elements are well-explored for these motifs, transition elements have been less studied and lack high-performance materials. To address this gap, we investigated a series of noncentrosymmetric [Ba₄(Ba₆S)][(VO_xS_4–x)₆] (space group: P6₃), the first V-based salt-inclusion oxychalcogenides demonstrating phase-matched IR-NLO properties. We achieved this by cation–anion module cosubstitution in the centrosymmetric structure of [Ba₄(Ba₆Cl₂)][(VO₄)₆] (space group: P6₃/m). The novel [Ba₄(Ba₆S)][(VO_xS_4–x)₆] features isolated heteroanionic [VO_xS_4–x]^3– units, charge-balanced Ba²⁺ cations, and a one-dimensional cationic chain of [Ba₆S]¹⁰⁺ octahedral units. Moreover, [Ba₄(Ba₆S)][(VO₃S)₆] exhibits notable properties including a high second-harmonic-generation intensity (1.33 × AgGaS₂@2900 nm), a substantial laser-induced damage threshold (7.65 × AgGaS₂), a broad IR cutoff edge (up to 11.2 μm), and significant birefringence for phase matching (Δn = 0.073@2900 nm). Structural analysis and DFT calculations demonstrate that the configuration of the [VO₃S]^3– units enhances NLO properties and increases structural anisotropy. Our findings suggest that V-based salt-inclusion oxychalcogenides are a promising class for IR-NLO applications and highlight cation–anion module cosubstitution as an effective approach for creating high-performance heteroanionic NLO crystals.

中文翻译：

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通过在 V 基盐包合物中实现阳离子-阴离子模块共取代实现平衡的 IR 非线性光学性能


氧硫属化物因其多样化的异阴离子功能基序而成为红外非线性光学 （IR NLO） 应用的显着竞争者。然而，虽然这些基序的主要组元素得到了很好的探索，但过渡元素的研究较少，并且缺乏高性能材料。为了解决这一差距，我们研究了一系列非中心对称 [Ba₄（Ba₆S）][（VO_xS_4–x）₆]（空间群：P6₃），这是第一个基于 V 的盐夹杂物，表现出相位匹配的 IR-NLO 特性。我们通过在 [Ba₄（Ba₆Cl₂）][（VO₄）₆]（空间群：P6₃/m））的中心对称结构中阳离子-阴离子模块共取代来实现这一点。新颖的 [Ba₄（Ba₆S）][（VO_xS_4–x）₆] 具有孤立的异阴离子 [VO_xS_4–x]^3– 单元、电荷平衡的 Ba²⁺ 阳离子和 [Ba₆S]¹⁰⁺ 八面体单元的一维阳离子链。此外，[Ba₄（Ba₆S）][（VO₃S）₆] 表现出显著的特性，包括高二次谐波产生强度 （1.33 × AgGaS₂@2900 nm）、相当大的激光诱导损伤阈值 （7.65 × AgGaS₂）、宽红外截止边缘（高达 11.2 μm）和显着的相位匹配双折射 （Δn = 0.073@2900 nm）。结构分析和 DFT 计算表明，[VO₃S]^3– 单元的构型增强了 NLO 特性并增加了结构各向异性。 我们的研究结果表明，V 基盐包涵杂硫系物是 IR-NLO 应用的一类很有前途的类别，并强调了阳离子-阴离子模块共取代是创建高性能异阴离子 NLO 晶体的有效方法。