一个对称萘酞菁的LB膜及其二阶非线性光学性质的研究

用水平提拉法制备了四叔丁基萘酞菁锌的LB膜。利用表面压-面积曲线、紫外-可见吸收光谱、小角X-射线衍射等表征了LB膜的结构，结果表明该化合物可以形成较高质量的具有很好层状结构的多层LB膜，在膜中分子大环平面垂直于基片平面并且以分子平面并不完全重合的H-聚集体存在。采用透射SHG方法测量了相应LB膜的二阶非线性光学性质，结果显示在实验条件下该化合物LB膜的宏观二阶非线性系数以及分子超极化率分别为X

A Novel Symmetrically Substituted Naphthalocyanine: Structure Character of LB Films and Second-Order Nonlinear Optical Properties

Langmuir-Blodgett films of tetra-tert-butyl naphthalocyaninatozinc(ttb-Nc), which is a novel symmetrically substituted naphthalocyanine derivative, have been fabricated by horizontal lifting technique and their structures have been characterized by the π-A isotherm, electronic absorption spectra, small-angle X-ray diffraction, coupled with the information deduced from the second-order nonlinear optical properties of the compound in the LB films. It concludes that LB films with good layer structure have came into being with the ttb-Nc molecules arranged themselves with H-aggregation, which is different from the conventional type one due to the macrocyclic planes of the ttb-Nc molecules in the aggregations have an incomplete overlapped configuration. Namely, the angle between the axis of this column-like H-aggregation of the ttb-Nc molecules and the macrocyclic planes of the compound is not just 90°. A staggered process for the ttb-Nc molecules to take this form of H-aggregation has been found after its solution spread onto the subphase surface. Particularly,second harmonic generation (SHG) from the LB films has also been detected. The macroscopic second-order susceptibility (X(2)) as well as the molecular hyperpolarizability (β) of the LB films for the compound under the experimental condition were estimated to be X(2) = 1.1 ～ 2.5 × 10 -9esu and β=2.1～4.7×10-31esu, respectively. In spite of the moderate high values of these two data, the research work expands the investigation field for the SHG materials.