螯合劑對有機非線性光學材料DAPSH之晶體生長與晶體性質的影響

Improving the Growth and Quality of DAPSH Crystals through the Addition of Chelating Agent

周慶偉(Ching-Wei Chou)

指導教授 ： 余琬琴

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2010年)

https://doi.org/10.6841/NTUT.2010.00264

摘要

有機非線性光學材料由於在數據儲存、光電、通訊技術等方面，有很高的應用價值，所以近年來獲得相當大的重視。設計得宜的有機非線性光學材料，其非線性光學性質遠比無機非線性光學材料優越，DAST (4-dimethylamino- N-methyl- 4-stilbazolium tosylate)就是個典型的例子。
DAPSH的全名是Trans- 4-(Dimethylamino)- N- phenyl- 4- stilbazolium Hexafluorosphate，是Coe et al. 於2002年發表的有機非線性光學材料。過去的研究顯示DAPSH的非線性光學性質與DAST 相當，相當具有發展潛力，但是其高品質的單晶製備不易是此類材料發展上的缺點，往往有成核數過多，晶體尺寸小又容易聚集的問題，因此本論文利用螯合劑的添加與溶劑比例的調配來改善這些問題。
本論文探討螯合劑（EDTA）的添加與乙腈/丙酮的比例對DAPSH晶體生長和晶體性質的影響，並以電子顯微鏡、分光光譜儀、X光繞射儀等儀器對晶體進行評價。結果顯示添加螯合劑可有效降低成核數，最佳的添加量約為20 ppm；且乙腈/丙酮的最佳比例約為1：1，能生長出的晶體品質最好。

關鍵字

非線性光學材料 ； 晶體生長 ； 螯合劑

並列摘要

In recent years, organic nonlinear optical (NLO) materials have stimulated great research interest because of their potential for various electro-optic (EO) and photonic applications, such as optical data processing and telecommunication. Compared to their inorganic counterparts, well-designed organic NLO materials can have much larger optical nonlinearities. A good example is DAST (4-dimethylamino- N-methyl- 4-stilbazolium tosylate), an organic salt known for its pronounced bulk quadratic NLO activity.
In 2002, Coe et al. reported a new stilbazolium salt, DAPSH （trans-4’- dimethylamino- N-phenyl- 4-stilbazolium hexafluorophosphate）, which was shown to possess a very high SHG（second harmonic generation）activity. DAPSH crystals exhibit a large second-order NLO coefficient（d111=290±40 pm/V at λ= 1.907 μm）, even higher than that of DAST（d111=210±55 pm/V at λ=1.907 μm）. However the reproducible growth of high quality, large DAPSH single crystals remains a challenging task. Very often too many nuclei are formed, resulting in crystals too small in size or clustered together and therefore unsuitable for device applications.
In this study, DAPSH crystals were grown from saturated solutions by the slow-cooling technique. The effects of chelating agent (EDTA) addition and solvent composition were invesitgated. The solvents used for crystal growth consisted of acetonitrile and acetone in various ratios. The solubilities of DAPSH in the solvents were found to increase with increasing acetonitrile-to-acetone ratio. The as-grown crystals were subjected to both structural and physical property studies, including x-ray diffraction, UV–visible spectroscopy, microhardness and electron microscopy analyses. The results show that the incorporation of the chelating agent EDTA greatly suppressed spurious nucleation and clustering of crystals, so that fewer crystals with larger sizes and higher quality were obtained from the EDTA-added solutions. The optimal EDTA concentration was about 20 ppm. Furthermore, crystal quality was also enhanced by using a solvent with lower solubility of DAPSH, i.e., a solvent with a low acetonitrile-to-acetone ratio.

並列關鍵字

Nonlinear optical materials ； crystal growth ； chelating agent

參考文獻

[36] 翁明堃, 新穎有機非線性光學材料DAPSH之晶體生長及性質分析, 碩士論文, 國立台北科技大學有機高分子研究所, 台北, (2008).

[37] 邱俊維, 有機非線性光學材料DAPSH晶體之製備及性質分析, 碩士論文, 國立台北科技大學有機高分子研究所, 台北, (2009).

[2] T. Kaino, B. Cai, and K. Takayama, Adv. Funct. Mater., (12), 599-603 (2002).

[7] D. F. Eaton., Science 253, (281), (1991).

[9] P.Günter, in Nonlinear Optical Effects and Materials, New York, (2000).