Using an ion-substitution strategy, herein, a new polar material, Pb₃(SeO₃)Br₄, with a greatly enhanced SHG response has been successfully designed and synthesized through a hydrothermal reaction. Pb₃(SeO₃)Br₄ crystallizes in the NCS space group P2₁2₁2₁ and consists of a three-dimensional framework formed by interconnecting one-dimensional chains, with a good thermal stability up to 230 °C. This compound exhibits a phase-matchable SHG response as strong as that of KH₂PO₄ (KDP) and a relatively wide mid-infrared (mid-IR) transparent window. Moreover, the optical band gap of Pb₃(SeO₃)Br₄ reaches about 3.35 eV, thus leading to a high laser damage threshold (LDT) of 67 MW cm⁻², which is over 12 times that of AgGaS₂ (<5 MW cm⁻²) measured under the same condition. All these findings suggest that Pb₃(SeO₃)Br₄ would be a candidate for an NLO material in the mid-IR region.

中文翻译：

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Pb ₃（SeO ₃）Br ₄：一种新的非线性光学材料，通过离子替代策略设计，具有增强的SHG响应†

通过使用离子取代策略，本文已经成功设计并通过水热反应合成了具有大大增强的SHG响应的新型极性材料Pb ₃（SeO ₃）Br ₄。Pb ₃（SeO ₃）Br ₄在NCS空间群P 2 ₁ 2 ₁ 2 _1中结晶，并由通过连接一维链形成的三维骨架组成，在高达230°C的温度下具有良好的热稳定性。该化合物表现出与KH ₂ PO ₄一样强的相匹配SHG响应（KDP）和相对较宽的中红外（mid-IR）透明窗口。此外，Pb ₃（SeO ₃）Br ₄的光学带隙达到约3.35 eV，从而导致67 MW cm ^-2的高激光损伤阈值（LDT），是AgGaS _2的12倍以上（<5 MW cm ^-2）在相同条件下测得。所有这些发现表明，Pb ₃（SeO ₃）Br ₄将成为中红外区域NLO材料的候选材料。