Processing Mechanically Reliable Flexible Organic Electronic Films

加工机械可靠的柔性有机电子薄膜用有机(碳基)半导体材料制成的印刷电子产品的发展导致了几种很有前途的技术，包括用于显示器的有机发光二极管、固态照明和有机光伏。与无机半导体材料相比，有机电子材料的优势在于其相对较低的成本和可获得性。然而，通常情况下，有机电子中使用的有源层和电极在使用过程中容易与水蒸气和/或氧气发生化学反应，从而降低了它们的寿命、效率和整体性能。鉴于封装在有机电子产品的可靠性中所起的作用以及对这些产品不断增长的需求，迫切需要开发用于组装这些器件的先进渗透屏障。当在使用过程中施加较大的应变时，这些阻挡膜还必须具有机械坚固性(防止开裂)。该奖项支持基础研究，为使用原子层沉积技术加工机械可靠的超薄聚合物阻挡层薄膜提供知识。此外，还计划为高中生提供暑期充实计划，以鼓励他们在STEM领域追求教育和职业生涯的兴趣。这项研究的主要目标是为柔性印刷电子设备中应用原子层沉积制备的超势垒薄膜的机械可靠性提供一个基本的了解。该实验方案将探索工艺条件、起始失效应变和材料成分/结构失效之间的关系，以阐明影响柔性电子设备中使用的原子分层沉积势垒可靠性的因素。这些薄膜与大多数原子分层沉积薄膜的不同之处在于，它们在低于100°C的温度下处理，以与低成本衬底和/或敏感的有机电子器件兼容。因此，这些原子分层沉积的薄膜的化学计量比可能与在较高温度下加工的薄膜完全不同，导致其特性尚未得到充分表征或了解。这项研究将提供一项系统的科学研究，以了解、预测和减少低温涂料的开裂，特别关注工艺条件(温度、聚合物基材的化学官能化)对其阻隔性能和机械性能的影响。这将通过将最先进的机械测试与表面科学和多尺度建模研究相结合来实现，这些研究将提供原子分层沉积涂层的化学计量比、其氢含量和分析的机械行为之间的联系。

Processing Mechanically Reliable Flexible Organic Electronic FilmsThe development of printed electronics made with organic (carbon-based) semiconductor materials has resulted in several promising technologies including organic light emitting diodes for displays, solid state lighting, and organic photovoltaics. The advantages of organic electronic materials are their relatively low cost and availability compared with inorganic semiconductor materials. However, in general, the active layers and electrodes used in organic electronics can be susceptible to chemical reactions with water vapor and/or oxygen during use, thereby reducing their lifetime, efficiency, and overall performance. There is a critical need to develop advanced permeation barriers for assembling these devices given the role the packaging has in the reliability of the organic electronics and the ever-increasing demand for these products. These barrier films must also be mechanically robust (resist cracking) when large applied strains are imposed during use. This award supports fundamental research to provide knowledge for the processing of mechanically reliable, ultrathin polymer barrier films processed with the atomic layer deposition technique. Additionally, summer enrichment programs are planned for high school students to encourage their interest in pursuing education and careers in STEM fields. The overarching goal of the proposed research is to provide a fundamental understanding of mechanical reliability of ultra-barrier films made by atomic layer deposition for application to flexible printed electronics. The experimental protocol will explore the relationship between processing conditions, onset failure strain, and material composition/structure failures to elucidate the factors that impact the reliability of atomic-layered-deposited barriers used in flexible electronics. These films differ from most atomic-layered-deposited film in that they are processed at temperatures below 100°C for compatibility with low cost substrates and/or sensitive organic electronic devices. Thus, the stoichiometry of these atomic-layered-deposited films can be quite different than those processed at higher temperatures, resulting in properties that are not fully characterized or understood. This research will provide a systematic scientific study to understand, predict and minimize cracking of low-temperature coatings, with a specific focus on the effects of processing conditions (temperature, chemical functionalization of the polymer substrates) on their barrier performance and mechanical properties. This will be enabled by coupling state-of-the-art mechanical testing with surface science and multi-scale modeling studies that will provide the link between the stoichiometry of the atomic-layered-deposited coatings, their hydrogen content, and the analyzed mechanical behavior.