Core Shell/Barrier Layer Structured Ceramics: Physical Mechanisms of Enhancements of the Desirable Dielectric Properties

电容器是储存电荷的装置，因此是几乎所有电机和现代电子设备的基本部件。对增加此类设备存储容量的持续需求，以及对功能稳定性和小型化的需求，使电容材料成为扩大研究和开发的一个有竞争力和有前途的领域，具有极高的实际创新和发现的潜力。电子元件行业在很大程度上依赖于卓越的电容器性能，这些元件立即影响全球市场，为更高效率的设备和新产品创新铺平了道路。因此，本研究的目的是探索基于钛酸钡陶瓷的优化电容器的结构局限性，并利用包括纳米技术在内的现代物理概念，在这些概念的基础上开发出优越的电容器系统和新器件。化石燃料的高成本使人们把注意力集中在发展替代能源转换和储存战略上。提出的研究的一个雄心勃勃的目标是开发一种电容器系统（超级电容器），将太阳能转换为电能并将其存储。这种太阳能可充电超级电容器可以彻底改变能源和运输技术，并广泛应用于各种传感器和存储设备。拟议的研究是多学科的，将涉及学生的参与，并与高中学生和他们的老师联系。在这些练习中获得的经验将大大提高他们的科学背景教育和对工程材料的认识。技术概述：钛酸钡（BaTiO3）仍然是电容器使用的首选介电材料，因为其固有的高介电常数，以及几乎无限的化学改性潜力，以提高介电和存储性能。优异的BaTiO3电容体系源于晶粒的核壳结构，掺杂引起的化学梯度导致应力-应变微畴和高极化。本研究将从实验和理论两方面对这些问题进行深入的探讨，以最大限度地减少存储电荷的渗透复合损失，从而产生高击穿电压和高介电常数。将详细分析晶粒尺寸对纳米级的影响，以确定和量化制备的微观结构中的梯度特征，并建立将这些结构与所展示的性能联系起来的分析关系。基于这些关联，提出的研究也将侧重于纳米结构超级电容器的制造方法。未来的目标是开发一种设备，可以收集阳光并将其作为电位能储存在超级电容器中。一种可能的策略是将染料敏化固态太阳能电池与纳米结构超级电容器集成在一起，这需要探索分离电荷重新组合所导致的损耗问题。拟议的工作范围是多学科的，涉及凝聚态物理、电子和材料科学、仪器分析和化学。这为研究生的培训提供了广阔的空间，也为本科生和高中生的动手实验提供了广阔的空间。

NON-TECHNICAL SUMMARY: Capacitors are devices which store electrical charge, and as such are essential components of almost all electrical machinery and modern electronic devices. The continuing need for increased storage capacity of such devices, as well as for functional stability and miniaturization, make capacitive materials a competitive and promising area for expanded research and development, with exceptionally high potential for practical innovations and discoveries of a fundamental nature. The electronic components industry depends heavily on superior capacitor performance, and such components immediately impact the global market, paving the way for higher efficiency devices and often to new product innovations. The aim of the proposed investigation, therefore, is to explore the structural limitations of optimized capacitors based on barium titanate ceramics, and to use modern physical concepts, including nanotechnology, to develop superior capacitor systems and new devices based on these concepts. The high cost of fossil fuels of necessity focuses attention on the development of alternate energy conversion and storage strategies. An ambitious goal of the proposed research is to develop a capacitor system (a supercapacitor) that will convert solar energy and store it as electrical energy. Such solar rechargeable supercapacitors can revolutionize energy and transportation technologies and be widely applied to various sensor and storage devices. The proposed research is multidisciplinary and will involve participation by students with outreach to high school students and their teachers. The experience gained in these exercises will significantly advance their science background education and awareness of engineering materials. TECHNICAL SUMMARY: Barium Titanate (BaTiO3) continues to be the preferred dielectric material for capacitor use, because of its inherently high dielectric constant, and almost limitless potential for chemical modification to enhance dielectric and storage properties. Superior BaTiO3 capacitative systems have originated from core-shell structuring of the grains, with chemical gradients induced by doping, leading to stress-strain micro-domains and high polarization. The proposed research will explore these issues in depth, experimentally and theoretically, with the aim of minimization of percolative recombination loss of the stored charge, yielding high breakdown voltages and high dielectric constants. Effects of grain dimensions down to the nanoscale will be analyzed in detail to identify and quantify gradient features in the prepared microstructures, and to develop analytical relationships linking these structures to exhibited properties. Based on these associations, the proposed study will also focus on fabrication methodologies for nanostructured supercapicitors. A futuristic goal will be to develop devices that can harvest sunlight and store it as electrical potential energy in the supercapacitor. A possible strategy might involve integration of a dye-sensitized solid-state solar cell with the nanostructured supercapacitor, requiring exploration of loss issues resulting from recombination of the separated charges. The proposed work is multidisciplinary in scope, involving condensed-matter physics, electronics and materials science, instrumentation analysis and chemistry. This gives wide scope for the training of graduate students, as well as outreach to and involvement of undergraduate and high school students in hands-on experiments.