Fabrication of Flexible Electronics by Laser-Aided Processing of Nanoparticles

该项目涉及通过利用纳米颗粒悬浮液的激光加工与直接微印刷相结合来制造高性能柔性电子产品。喷墨打印的金属纳米颗粒的激光烧结和烧蚀能够实现低温金属沉积以及高分辨率图案化，从而克服了喷墨直写的分辨率限制而无需任何光刻工艺。结合空气稳定的羧酸官能化聚噻吩，所有印刷和激光加工的有机场效应晶体管（OFFEs）与微米至亚微米的关键特征分辨率将在一个完全无掩模序列制造，消除了任何光刻工艺的需要。所有加工和表征步骤将在塑料相容的低温下进行。所制造的器件的特征在于，以优化性能的通道尺寸，空气稳定的半导体材料，短沟道效应和沟道粗糙度。为了提高可靠性，印刷介质层的厚度均匀性将得到改善。为了从根本上理解并最终优化工艺，将对激光与纳米颗粒材料相互作用的物理机制进行实验和理论研究。时间和光谱分辨监测技术，包括远场和近场光学探测将进行询问的相变，颗粒变形，烧结和烧蚀过程。原位透射电子显微镜（TEM）的研究将进行直接图像的键合序列与纳米分辨率。分子动力学（MD）模拟将与实验工作协调进行，以研究相变和烧结过程。为了便于数值模拟，将测量纳米材料的热，光学和电学特性。更广泛的影响金属纳米颗粒的低温激光加工消除了对光刻工艺的需求，并开辟了在柔性衬底上低成本、无掩模制造高分辨率电子器件的道路。利用该项目开发的技术的主要候选者包括显示器和大面积电子产品、互连、交叉导体、电容器、天线、化学传感器和柔性基板上的有源电子元件的制造。一系列潜在的应用可以预见的传感器和设备的制造的基础上的磁性，陶瓷和半导体纳米粒子。科学研究成果有望揭示激光与纳米颗粒材料相互作用中涉及的复杂现象。具体而言，它将阐明激光激发下的能量传递，熔化，烧结和烧蚀过程。

The project concerns the fabrication of high-performance flexible electronics by utilizing laser processing of nanoparticle suspensions in conjunction with direct micro-printing. Laser sintering and ablation of inkjet printed metal nanoparticles enables low temperature metal deposition as well as high-resolution patterning, thus overcoming the resolution limitation of inkjet direct writing without any lithography processes. Combined with air stable carboxylate-functionalized polythiophene, all-printed and laser processed organic field effect transistors (OFETs) with micron to submicron critical feature resolution will be fabricated in a fully maskless sequence, eliminating the need for any lithographic processes. All processing and characterization steps will be carried out at plastic-compatible low temperatures. The fabricated devices will be characterized in order to optimize the performance in terms of the channel size, the air stable semiconductor material, the short channel effect and the channel roughness. To increase reliability, the thickness uniformity of the printed dielectric layer will be improved.For fundamental understanding and ultimately for process optimization, both experimental and theoretical investigations will be conducted on the physical mechanisms of the laser light interaction with the nanoparticle material. Temporally and spectrally resolved monitoring techniques, including far-field and near-field optical probing will be performed to interrogate the phase transition, particle deformation, sintering and ablation processes. In-situ transmission electron microscopy (TEM) studies will carried out to directly image the bonding sequence with nanometer resolution. Molecular dynamics (MD) simulations will be carried out in coordination with the experimental work to investigate the phase transition and sintering processes. To facilitate the numerical simulations, thermal, optical and electrical properties of the nanomaterial will be measured. Broader ImpactThe reduced temperature, laser-based processing of metal nanoparticles eliminates the need for lithographic processes and opens the way to the low-cost, maskless fabrication of high-resolution, electronic devices on flexible substrates. Prime candidates for the utilization of the technology developed in this project include the manufacture of displays and large area electronics, interconnections, crossover conductors, capacitors, antennae, chemical sensors and active electrical components on flexible substrates. A spectrum of potential applications can be envisioned for the fabrication of sensors and devices based on magnetic, ceramic and semiconductor nanoparticles. The scientific research outcome is expected to shed light on complex phenomena involved in the laser interactions with nanoparticle materials. Specifically, it will elucidate the energy transfer, melting, sintering and ablation processes under laser excitation.