含偶氮分子的ormocer固体薄膜制备及二阶光学非线性

Fabrication of Ormocer Films Containing Azo dye Molecules and Their Optical Second Order Nonlinearities

利用溶胶 凝胶 (sol gel)低温合成非晶态技术 ,以γ 氨基丙基三乙氧基硅烷 (3 aminopropyl triethoxysilane ,KH5 5 0 )与γ 缩水甘油醚基丙基三甲氧基硅烷 (3 glycidoxy propltrimethoxysilane ,KH5 6 0 )为先驱体 ,把DisperseOrange3(DO3)偶氮分子以 3wt%浓度掺杂到上述溶胶与ormocer(organicmodifiedceramic)体系中。在ITO片上制备成厚度为 4μm的DO3/90KH5 6 0 10KH5 5 0薄膜。经高温电晕极化后 ,用二次谐波发生装置 ,测量出薄膜材料的二次谐波强度 ,并计算出经极化后薄膜材料的 p→p的二阶有效极化系数deff=0 11pm/V。极化 2 4小时后 ,其SHG强度基本保持不变 ,大约为刚极化后的 80 %大小。我们认为这主要是由于介质中KH5 5 0的引入 ,其中 -NH2 基团与DO3中的 -NH2 之间形成了氢键的作用 ,以及由氢键引起的介质材料进一步致密化作用 ,使得DO3分子不易发生弛豫作用 ,而保持极化后的分子状态。

Using 3 aminopropyltriethoxysilane(KH550) and 3 glycidoxypropltrimethoxy silane(KH560) as precursors, Disperse Orange 3 (DO3) was doped into above sol and ormocer in 3wt% concentration, and the sol gel derived films with 4μm thickness coated on ITO film were fabricated. Corona poling was performed by applying a high voltage of +5kV to a needle electrode. After corona poling of the film at 185° for 4 hours, about 1/5 of DO3 molecules remained in solid state film, estimating from their spectra, and the concentration of DO3 molecule in poled film was estimated about 1 6×10 19 cm -3 . Second harmonic generation (SHG) was used to probe the size and stability of the orientational order of the poled films. The second harmonic intensity of the films was measured using p (parallel polarized) excitation and p detection, and compared with that generated by a y cut quartz crystal. No Maker fringe pattern for the film was observed , we could assume that the coherence length was much larger than the film thickness. The SHG intensity increases with increasing angle and reaches to maximum at θ =52°. The effective second order nonlinear coefficient, d eff and d 33 were estimated about 0 11pm/V and 0 14pm/V, respectively, and the intensity of SHG decreased slightly and remained ～80% of the initial value even after poling 500 hours. It is thought that for a combination of DO3 and organic inorganic gel the pore shrinkage and high baking temperature stabilize the nonlinearity in particular. Furthermore, due to leading KH550 (containing -NH 2 group) into sol gel derived matrix, it is expected that the hydrogen bonds between DO3 and KH550 in matrix are formed and the more density of matrix is reached, which can keep the oriented DO3 stable.