Preparation of Nanopartide-dispersed Hybrid-Polymer Nonlinear Optoelectronic Materials and Phase Control

纳米颗粒分散杂化聚合物非线性光电材料的制备及相位控制

基本信息

批准号：
15360341
负责人：
WADA Satoshi
金额：
$ 8.77万
依托单位：
TOKYO INSTITUTE OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15360341/
关键词：
Barium titanate Nanoparticle Size effect Hybrid-Polymer Materials 3D colloidal crystal Far infrared Reflection Phonon analysis Soft mode 無機-有機ハイブリッドインクプロピレンカーボネイト精密構造解析

项目摘要

A new preparation method was proposed to prepare impurity-free, defect-free barium titanate (BaTiO_3) nanoparticles using barium titanyl oxalate. This method was called a 2-step thermal decomposition method, and composed of the following two steps ; i.e., (1)1^<st> step : a preparation of intermediate compound of Ba_2Ti_2O_5CO_3 by thermal decomposition of barium titanyl oxalate in air and (2) 2^<nd> step : a preparation of BaTiO_3 nanoparticles via thermal decomposition of Ba_2Ti_2O_5CO_3 in vacuum. As the results of characterization using many kinds of measurements such as density, impurity, TG-DTA, FT-IR, Raman, TEM observation, Raman and so on, it was cleared that these BaTiO_3 nanoparticles were defect-free, impurity-free, and dense. However, there was no way to measure dielectric constant of particles. Thus, a new measurement method for powder dielectric constants was newly developed. The powder dielectric measurement of BaTiO_3 fine particles with sizes from 17 to 1,000 nm revea … More led the maximum dielectric constant at a certain particle size. Moreover, the sizes with maximum dielectric constants were strongly dependent on the preparation methods. When the BaTiO_3 fine particles were prepared using the original 2-step thermal decomposition method, a dielectric constant maximum of 15,000 was observed at 70 nm particle size. On the other hand, when the BaTiO_3 fine particles were prepared using the modified 3-step thermal decomposition method, a dielectric constant maximum of 5,000 was observed at 140 nm. To confirm the validity of these high dielectric constants, particle/polymer composite using these particles was prepared and these dielectric properties were measured. As the result, the particle/polymer composite using the high dielectric constant showed always much higher dielectric constants than those prepared using the normal dielectric constant of 3,000. The former BaTiO_3 was prepared in vacuum of 10^<-2> torr while the latter BaTiO_3 was prepared in air. Structure refinement of BaTiO_3 particles using a Rietveld method revealed that all of BaTiO_3 particles were always composed of two parts ; (a)surface cubic layer and (b)bulk tetragonal layer. Moreover, a thickness of surface cubic layer for BaTiO_3 nanoparticles prepared in vacuum of 10^<-2> torr was much thinner than that for BaTiO_3 nanoparticles prepared in air. Thus, to explain these differences, a new model on the basis of "surface relaxation" was proposed. Moreover, to measure phonon state of these particles, 3D colloidal crystals with a smooth surface were prepared, and their far infrared reflection spectra were measured. To date, there was no way to measure phonon state of nanoparticles except for Raman scattering, but using the 3D colloidal crystals, the clear far infrared reflection spectra were obtained. By the analysis of these spectra, soft mode frequency was determined for various BaTiO_3 nanoparticles. As the result, it was cleared that the dielectric constant of BaTiO_3 particles increased with decreasing soft mode frequency. Moreover, the decrease of soft mode frequency was strongly related to the thickness of surface cubic layer. Less

提出了一种利用草酸氧钛钡制备无杂质、无缺陷的钛酸钡（BaTiO_3）纳米粒子的新方法，该方法被称为两步热分解法，由以下两个步骤组成： )1^<st>步骤：草酸氧钛钡在空气中热分解制备中间体化合物Ba_2Ti_2O_5CO_3 (2)第二步：通过Ba_2Ti_2O_5CO_3在真空中热分解制备BaTiO_3纳米颗粒作为使用密度、杂质、TG-DTA、FT-IR、拉曼等多种测量的表征结果， TEM观察、拉曼等表明，这些BaTiO_3纳米颗粒无缺陷、无杂质、致密。由于无法测量颗粒的介电常数，因此，新开发了一种新的粉末介电常数测量方法，测量尺寸为 17 至 1,000 nm 的 BaTiO_3 细颗粒的粉末介电常数，得出了最大介电常数。此外，具有最大介电常数的尺寸强烈依赖于制备方法。当使用原始的两步热分解法制备BaTiO_3细颗粒时，介电常数。在70 nm粒径处观察到介电常数最大值为15,000，另一方面，当使用改进的三步热分解法制备BaTiO_3细颗粒时，在140 nm处观察到介电常数最大值为5,000。制备这些高介电常数的颗粒/聚合物复合材料，并测量这些介电性能。结果，使用高介电常数的颗粒/聚合物复合材料显示出这些介电性能。其介电常数总是比使用3,000的正常介电常数制备的介电常数高。前者的BaTiO_3是在10^-2托的真空中制备的，而后者的BaTiO_3是使用Rietveld方法在空气中制备的。所有BaTiO_3颗粒总是由两部分组成：(a)表面立方层和(b)块状四方层。此外，表面立方层的厚度。在10^-2托真空下制备的BaTiO_3纳米粒子比在空气中制备的BaTiO_3纳米粒子薄得多。因此，为了解释这些差异，提出了基于“表面弛豫”的新模型。为了测量这些粒子的声子态，制备了具有光滑表面的3D胶体晶体，并测量了它们的远红外反射光谱，迄今为止，还没有办法测量声子态。除了拉曼散射之外，还使用 3D 胶体晶体，获得了清晰的远红外反射光谱。通过对这些光谱的分析，确定了各种 BaTiO_3 纳米颗粒的软模式频率，结果表明电介质。 BaTiO_3颗粒的常数随软模频率的降低而增大，而且软模频率的降低与表面立方层的厚度密切相关。

项目成果

期刊论文数量（60）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

THz Region Dielectric Properties of Barium Titanate Fine Particles using Infrared Reflection Method

红外反射法测定钛酸钡细颗粒的太赫兹区介电性能

DOI：
发表时间：
2005
期刊：
Journal of the European Ceramic Society (In press)
影响因子：
0
作者：
S.Anisul Haque;Masahiko Yamamoto;Ryoichi Nakatani;Yasushi Endo;Y.Q.Li;Satoshi Wada
通讯作者：
Satoshi Wada

Development of New Preparation Method for nm-sized Barium Titanate Particles

纳米级钛酸钡颗粒制备新方法的开发