KC9H5O6(H2O): A Promising UV Nonlinear-Optical Material with Large Birefringence Based on a π-Conjugated (C9H5O6)− Group
KC9H5O6(H2O): A Promising UV Nonlinear-Optical Material with Large Birefringence Based on a π-Conjugated (C9H5O6)− Group
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KC9H5O6(H2O)：一种基于α-共轭 (C9H5O6) 基团的具有大双折射的有前途的紫外非线性光学材料
DOI：
10.1021/acs.inorgchem.2c02521
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发表时间：
2022
影响因子：
4.6
通讯作者：
Dong Yan
中科院分区：
文献类型：
--
作者：
Shu-Fang Li;Liang Hu;Ru-Ling Tang;Yao Ma;Fei-Fei Mao;Jie Zheng;Xiu-Du Zhang;Dong Yan
为了满足激光技术和光学行业不断增长的需求，我们的目标是找到具有大非线性光学 (NLO) 系数和双折射的合适基本构建模块，以实现高性能 NLO 或双折射系统。通过初步研究和计算，发现平面π共轭基团(C9H5O6)−具有较大的极化率各向异性(δ)和超极化率(βmax)，与(B3O6)3–、(C3N3O3)3–等众所周知的基团相当。在此，我们报道了一种新的碱金属3,5-二羧基苯甲酸盐， KC9H5O6(H2O) (KH2BTC)，在无心空间群Pna21中结晶。 KH2BTC 在 1064 nm 激光辐射下的二次谐波产生 (SHG) 测量表明，KH2BTC 的 SHG 响应是具有 I 型相位匹配行为的 KDP 的 1.2 倍。双折射测量表明，KH2BTC 在 550 nm 处具有约 0.372 的大双折射。紫外（UV）漫反射光谱得到的KH2BTC带隙为3.91 eV，表明KH2BTC具有作为UV NLO或双折射材料的潜在应用。理论计算进一步证实，KH2BTC令人印象深刻的光学性质源自(C9H5O6)−阴离子的大极化率各向异性。
In order to meet the growing needs for the laser technology and optics industries, the goal is to find suitable fundamental building blocks with large nonlinear-optical (NLO) coefficients and birefringence for an excellent-performance NLO or birefringent system. Via preliminary investigations and calculations, it has been found that the planar π-conjugated group (C9H5O6)−possesses large polarizability anisotropy (δ) and hyperpolarizability (βmax), comparable to well-known groups such as (B3O6)3–, (C3N3O3)3–, etc. Herein, we report a new alkali-metal 3,5-dicarboxybenzoate, KC9H5O6(H2O) (KH2BTC), which crystallized in the acentric space groupPna21. Second-harmonic-generation (SHG) measurements of KH2BTC under 1064 nm laser radiation show that the SHG response of KH2BTC is 1.2 times that of KDP with type I phase-matching behavior. Birefringence measurements show that KH2BTC owns a large birefringence of about 0.372 at 550 nm. The band gap of KH2BTC obtained by ultraviolet (UV) diffuse-reflectance spectroscopy is 3.91 eV, indicating that KH2BTC has potential applications as UV NLO or birefringent materials. Theoretical calculation further confirmed that the impressive optical properties of KH2BTC are derived from the large polarizability anisotropy of the (C9H5O6)−anions.