Xinjiang Key Laboratory of Electronic Information Materials and Devices, Xinjiang Technical Institute of Physics & Chemistry, Chinese Academy of Sciences, Urumqi 830011, China.
J Am Chem Soc. 2013 Mar 20;135(11):4215-8. doi: 10.1021/ja400500m. Epub 2013 Mar 12.
The generation of intense coherent deep-UV light from nonlinear optical materials is crucial to applications ranging from semiconductor photolithography and laser micromachining to photochemical synthesis. However, few materials with large second harmonic generation (SHG) and a short UV-cutoff edge are effective down to 200 nm. A notable exception is KBe2BO3F2, which is obtained from a solid-state reaction of highly toxic beryllium oxide powders. We designed and synthesized a benign polar material, Ba4B11O20F, that satisfies these requirements and exhibits the largest SHG response in known borates containing neither lone-pair-active anions nor second-order Jahn-Teller-active transition metals. We developed a microscopic model to explain the enhancement, which is unexpected on the basis of conventional anionic group theory arguments. Crystal engineering of atomic displacements along the polar axis, which are difficult to attribute to or identify within unique anionic moieties, and greater cation polarizabilities are critical to the design of next-generation SHG materials.
从非线性光学材料中产生强相干深紫外光对于从半导体光刻和激光微加工到光化学合成等应用至关重要。然而，很少有材料具有大的二次谐波产生（SHG）和短的紫外截止边缘，能够有效降低到 200nm。一个值得注意的例外是 KBe2BO3F2，它是通过高度有毒的氧化铍粉末的固态反应获得的。我们设计并合成了一种良性的极性材料 Ba4B11O20F，它满足这些要求，并在已知的硼酸盐中表现出最大的 SHG 响应，这些硼酸盐既不含有孤对活性阴离子，也不含有二阶 Jahn-Teller 活性过渡金属。我们开发了一个微观模型来解释这种增强，这是基于传统的阴离子基团理论论点所意想不到的。沿着极轴的原子位移的晶体工程，这很难归因于或在独特的阴离子基团内识别，以及更大的阳离子极化率，对于下一代 SHG 材料的设计至关重要。
