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摘要分子铁电材料因为其简便经济的制备过程和优良的机械性能，被极其广泛的需求。高氯酸咪唑(C3N2H5ClO4)是一种新型的分子铁电材料，从水溶液中制备出其晶体的宝盒极化强度达到10微库伦每平方厘米，居里温度高达373卡尔文，同时其具备高介电常数，低介电损耗的特点。高氯酸咪唑显示出良好的压电响应和清晰的铁电畴结构。这些特性使得高氯酸咪唑能够在传感器，数据存储，电光控制等领域与钙钛矿结构铁电材料和聚合物铁电材料相抗衡。23720
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本文采用溶液挥发法在透明可弯曲衬底上制备了高氯酸咪唑薄膜样品，首先利用紫外-可见光分光计测试其透光率，并计算了禁带宽度。接着使用XRD表征了其晶体结构，然后使用原子力显微镜观察了薄膜表面形貌,并利用原子力显微镜的压电力模块测得不同温度下的铁电畴，并观测到薄膜在弯曲状态下铁电畴的变化情况。 最后通过铁电测试仪测试了高氯酸咪唑薄膜的宏观铁电性，证明了其实际应用价值。
关键词 分子铁电 薄膜 铁电畴 原子力显微镜
毕业设计说明书（毕业论文）外文摘要
Title Control The Photoelectric Properties of Transparent and Flexible Ferroelectric Thin Films by Strain
Abstract
Molecular ferroelectrics are highly desirable for their easy and environmentally friendly processing and mechanical flexibility. We found that C3N2H5ClO4 , a molecular crystal processed from aqueous solution, is a ferroelectric with a spontaneous polarization of 10 micro coulombs per square centimeter, high Curie temperature of 373 Kelvin , large dielectric constant, and low dielectric loss. C3N2H5ClO4 exhibits good piezoelectric response and well-defined ferroelectric domains. These attributes make it a molecular alternative to perovskite ferroelectrics and ferroelectric polymers in sensing, data storage, electro-optics and other fields.
In this paper, a series of thin films of C3N2H5ClO4 are prepared on transparent and flexible substrates by the method of solution evaporating. Ultraviolet spectrophotometer is used to determine light transmittance and calculate the forbidden bandwidth. X-ray diffraction is used to characterize the crystal structure. Surface topography, electric domain structure under different temperatures and the dynamic process of electric domain structure under strain are obtained with the aid of AFM/PFM. The value of practical application has been confirmed using Ferroelectric Tester.
Keywords molecule ferroelectric thin film domain AFM
目录
1 引言 1
1.1 铁电体概述 1
1.2 有机铁电体研究的兴起 4
1.3 高氯酸咪唑的研究现状与前景 6
2．实验设计 6
2.1实验药品及仪器 6
2.2高氯酸咪唑薄膜的制备 7
2.3高氯酸咪唑薄膜的性能表征 8
2.3.1透光率测试 8
2.3.2 X射线衍射 8
2.3.3薄膜表面形貌和畴结构 9
3.实验数据分析 11
3.1 透光率和禁带宽度 11
3.2 X射线衍射 12
3.3薄膜表面形貌和畴结构 13
3.4 铁电回线 19
结论 21
致 谢 22
参考文献23
1 引言
1.1 铁电体概述
铁电性 (piezoelectricity)是指有自发极化，且其方向可以通过电场逆转[1]的性能。对晶体的对称性分析之后可以得出如下结论，所有的铁电体除了具有铁电性以外，也会同时显示热电(pyroelectricity)，压电性(piezoelectricity) [2-5,8]，以及二次谐波（SHG）发射的性能。