Phase-Change Behavior and Nonlinear Optical Second and Third Harmonic Generation of the One-Dimensional K(l-x)CsXPSe6 and Metastable β-CsPSe6
Phase-Change Behavior and Nonlinear Optical Second and Third Harmonic Generation of the One-Dimensional K(l-x)CsXPSe6 and Metastable β-CsPSe6
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DOI：
10.1021/acs.chemmater.5b00065
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发表时间：
2015-03-10
影响因子：
8.6
通讯作者：
Kanatzidis, Mercouri G.
中科院分区：
文献类型：
--
作者：
Haynes, Alyssa S.;Saouma, Felix O.;Kanatzidis, Mercouri G.
研究了APSe（6）（A = K，K（1-x）Csx，Cs）系列一维（1D）材料的非线性光学（NLO）响应，考察了阳离子尺寸对非线性光学响应的影响.该系列具有高性能的NLO特性，非中心对称母体材料KPSe 6具有1/（无穷大）[PSe 6-]的无限一维链。这种结构已成功地取代铯高达K0.6Cs0.4PSe6，同时保留极性特征。所有化合物都在Pca 2（1）空间群中结晶，并且具有2.1eV的带隙。使用同步辐射的原位粉末X射线衍射实验用于确定APSe（6）系统的非晶到结晶行为以及结晶和熔融动力学的细节。这些测量揭示了一种新相β-CsPSe 6，它是亚稳态的，在bar 2（1）c上的非中心对称四方空间群P（4）中结晶，a = 12.526（2）埃，c = 12.781（3）埃，V = 2005.3（6）埃（3），Z = 8。该结构由两组相互垂直的1/8[PSe 6-]链组成，由Cs阳离子进行电荷平衡，β-CsPSe 6的带隙为1.9 eV。二次谐波产生（SHG）测量表明，将Cs取代到KPSe 6中保持了具有非常高的SHG系数（chi（2））的强NLO信号，对于K（1-x）CsxPSe 6类似于150 pm/V，对于β-CsPSe 6类似于30 pm/V。激光诱导损伤阈值分析表明，APSe（6）在1064 nm处表现出双光子吸收（2 PA），输入激光强度大于1 GW/cm（2），并且2 PA的光学损伤近似于2 GW/cm（2）。该材料还表现出强的三次谐波产生（THG），对于KPSe 6、K0.6Cs0.4PSe6、α-CsPSe 6和β-CsPSe 6，THG系数（χ（3））× 10（5））分别为2.6、3.1、1.8和1.1 μ m（2）/V-2。
The APSe(6) (A = K, K(1-x)Csx, Cs) family of one-dimensional (1D) materials was studied to examine the effects of the cation size on the nonlinear optical (NLO) response. The family has high-performing NLO properties with the noncentrosymmetric parent material, KPSe6, having infinite 1D chains of 1/(infinity)[PSe6-]. This structure has been successfully substituted with cesium up to K0.6Cs0.4PSe6 while retaining the polar character. All compounds crystallize in the space group Pca2(1) and have band gaps of 2.1 eV. In situ powder X-ray diffraction experiments using synchrotron radiation were used to determine the specifics of the amorphous to crystalline behavior and the crystallization and melting kinetics of the APSe(6) system. These measurements revealed a new phase, beta-CsPSe6, which is metastable and crystallizes in the noncentrosymmetric tetragonal space group P (4) over bar2(1)c with a = 12.526(2) angstrom, c = 12.781(3) angstrom, V = 2005.3(6) angstrom(3), and Z = 8. The structure is composed of 2 sets of mutually perpendicular 1/8[PSe6-] chains charge-balanced by Cs cations, and the band gap of beta-CsPSe6 is 1.9 eV. Second harmonic generation (SHG) measurements demonstrate that substitution of Cs into KPSe6 maintains the strong NLO signal with a very high SHG coefficient (chi((2))) of similar to 150 pm/V for K(1-x)CsxPSe6 and 30 pm/V for beta-CsPSe6. Laser-induced damage threshold analysis reveals APSe(6) exhibits two-photon absorption (2PA) at 1064 nm with input laser intensity greater than 1 GW/cm(2) and optical damage from 2PA at similar to 2 GW/cm(2). The materials also exhibit strong third harmonic generation (THG) with THG coefficients (chi((3)) x 10(5)) for KPSe6, K0.6Cs0.4PSe6, alpha-CsPSe6, and beta-CsPSe6 to be 2.6, 3.1, 1.8, and 1.1 pm(2)/V-2, respectively.