ERI: Enabling tunable electronic device fabrication on flexible substrates using Barium Strontium Titanate (BST) printable ink development

印刷或加法制造作为一种低成本、高分辨率、快速制作一系列复杂电路的原型具有应用潜力。这项工作中提出的印刷可调器件将允许电路功能的电气调谐，与机械可调电气设备相比，大大降低了整个电路的成本、占地面积和重量。这些印刷的可调谐电子设备对国家安全至关重要，尤其是无线电通信。此外，低成本物联网(IoT)和可穿戴设备将显著受益于拟议的可调柔性电子设备。然而，目前还没有可调谐打印墨水来在柔性衬底上制造可调谐电子器件。此外，现有的可打印材料需要高温处理(大于800°C)才能达到所需的可调性，这将损坏大多数类型的柔性基板，如塑料、纸张和织物。与可打印油墨相关的多个挑战和独特的瓶颈，目前正在进行的解决这些问题的研究工作有限。该项目将涵盖新型可调材料的合成，可打印墨水的开发，以及可调电子设备的设计、模拟和制造。该项目将开启可调谐柔性电子设备的新范例。本科生和研究生都将直接受益于这一项目，拟议的教育推广项目将提高中学生对理工科职业的兴趣和意识。此外，拟议项目的新发现将被整合到研究生水平的印刷电子学相关教学中。该项目将全面促进对无烧结钛酸锶(BST)纳米颗粒用作柔性电子产品的可调材料的基本理解。将确定在室温(无需烧结)下实现尽可能高的介电常数和可调性的BST纳米颗粒的组成。深入研究了BST纳米粒子的组成、大小和堆积密度对介电可调性的影响。利用电场作用下无烧结BST纳米颗粒的高分辨率X射线衍射图，研究了晶格参数的变化与介电可调性之间的关系。这将使人们更深入地了解无烧结BST纳米颗粒的介电可调性，目前还没有实验报道。将所需的偏置电压降低到25伏以下是一项重大成就，使印刷可调柔性器件能够在实际应用中使用，例如移相器、频率选择表面和相控阵天线。这些设备目前还不适用于实际应用。这项拟议的工作将极大地促进关于无烧结BST纳米颗粒作为可调材料、用于直写打印技术的纳米颗粒油墨配方以及柔性基板上的全印刷可调无线电和微波频率器件的知识。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Printed or additive manufacturing has application potential as a low-cost, high-resolution, fast prototyping of a range of complex circuits. Printed tunable devices proposed in this work will allow the electrical tuning of circuit functions, drastically reducing the cost, footprint, and weight of the overall circuitry compared to mechanically tunable electrical devices. These printed tunable electrical devices are critical to national security, especially radio communications. In addition, low-cost Internet of Things (IoT) and wearable devices will significantly benefit from the proposed tunable flexible electrical devices. However, currently, there are no tunable printable inks to fabricate tunable electrical devices on flexible substrates. In addition, existing printable materials need high-temperature processing (greater than 800 °C) to achieve the required tunability, which will damage most types of flexible substrates, such as plastics, paper, and fabrics. Multiple challenges and unique bottlenecks are associated with printable inks, and there are limited ongoing research efforts to solve these issues. This project will cover novel tunable materials syntheses, printable ink development, and the design, simulation, and fabrication of tunable electrical devices. This project will open a new paradigm of tunable flexible electronic devices. Both undergraduate and graduate students will directly benefit from this project, and the proposed educational outreach projects will enhance middle school students' interest and awareness of science and engineering careers. In addition, the proposed project's novel findings will be integrated into graduate-level printed electronics-related teaching.This project will comprehensively advance the fundamental understanding of the utilization of sinterless Barium Strontium Titanate (BST) nanoparticles as a tunable material for flexible electronics. The composition of BST nanoparticles to achieve the highest possible dielectric constant and tunability at room temperature (without sintering) will be identified. An in depth investigation will be carried out to determine the effects of the Ba:Sr molar fraction, the size, and the packing density of BST nanoparticles on dielectric tunability. High-resolution X-Ray diffraction patterns of sinterless BST nanoparticles under an applied electric field will be used to investigate the correlation between the variation of lattice parameters and the dielectric tunability. This will give a greater insight into the dielectric tunability of sinterless BST nanoparticles, which have not been experimentally reported yet. Lowering the required bias voltage to less than 25 Volts is a significant achievement that enables the usage of printed tunable flexible devices in real-world applications, such as phase shifters, frequency-selective surfaces, and phased array antennas. These devices are not currently feasible for real-world applications. The proposed work will significantly advance the knowledge of sinterless BST nanoparticles as a tunable material, nanoparticle ink formulation for direct-write printing technologies, and fully printed tunable radio and microwave frequency devices on flexible substrates.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.