Fabrication of Flexible Electronics by Laser-Aided Processing of Nanoparticles

该项目涉及利用激光加工纳米颗粒悬浮液并结合直接微型印刷来制造高性能柔性电子产品。激光烧结和烧蚀喷墨打印金属纳米颗粒可以实现低温金属沉积和高分辨率图案化，从而克服了无需任何光刻工艺的喷墨直写的分辨率限制。与空气稳定的羧酸盐功能化聚噻吩相结合，全印刷和激光处理的具有微米到亚微米关键特征分辨率的有机场效应晶体管(OFET)将以完全无掩模的顺序制造，消除了任何光刻工艺的需要。所有加工和表征步骤都将在与塑料兼容的低温下进行。为了在沟道尺寸、空气稳定的半导体材料、短沟道效应和沟道粗糙度方面优化性能，将对所制备的器件进行表征。为了提高可靠性，印刷电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。将采用时间和光谱分辨的监测技术，包括远场和近场光学探测，以询问相变、颗粒变形、烧结和烧蚀过程。将进行原位透射电子显微镜(TEM)研究，以直接以纳米分辨率成像键序列。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、光和电学性质。更广泛的影响温度更低、基于激光的金属纳米颗粒加工消除了光刻工艺的需要，并为在柔性基板上以低成本、无掩模制造高分辨率电子设备开辟了道路。该项目开发的技术的主要用途包括在柔性衬底上制造显示器和大面积电子产品、互连、交叉导体、电容器、天线、化学传感器和有源电子元件。基于磁性、陶瓷和半导体纳米颗粒的传感器和器件的制造可以预见到一系列潜在的应用。这一科学研究成果有望揭示激光与纳米材料相互作用所涉及的复杂现象。具体地说，它将阐明激光激励下的能量传递、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.