Organic (semi)conducting materials for 3D printed electronic sensing devices

符合各种外形因素的电子设备是在物联网的包装、可穿戴设备和连接对象中集成传感和光电子技术的必要条件之一。有机(半)导电材料方面的进展证明，这类化合物在实现高度顺应性、可持续性和成本效益的器件方面发挥着关键作用。实际上，有机电子元件的机械性能可以与支撑(软)衬底和要与该器件叠层的目标物体的机械性能相匹配。虽然在软性和可打印设备的背景下开发合成和加工策略以优化有机电子化合物是一个蓬勃发展的研究领域，但人们对解决与其在对象中的单片集成相关的挑战有着浓厚的兴趣。这种集成将消除层压步骤的需要和与衬底的机械性能相关的约束，从而导致自立式有机电子器件的自由形式设计。在这个泛加拿大合作项目中，我们概述了使用有机(半)导电材料来制备三维(3D)打印电子传感技术的方法。尽管《2021年柔性打印电子产品路线图》提到，3D打印电子产品的市场规模预计将在2025年达到10亿美元，但它也强调了3D打印电子产品是一个新兴领域。有机(半)导电化合物的3D打印研究的匮乏清楚地表明了基础知识方面的空白，需要通过这项研究来填补。例如，由商品聚合物和碳纳米材料制成的用于熔融沉积建模的导电丝可以在商业上获得。然而，在制备过程中使用卤化溶剂，加上未披露的混合物成分以及电导率值逐批变化，阻碍了在可持续制备有机电子传感器件的背景下建立可靠的结构-加工-性能关系。为了克服这些挑战，我们将利用我们团队成员的有机电子专业知识，分别在有机电子还原染料的合成(Morin)、高级制造(3D打印)和功能聚合物材料的表征(Laventure)以及软半导体和晶体管传感器设计(Rondeau-gagné)方面发挥协同作用。我们的目标是1)开发一种用于有机电子半导体溶液和全聚合物导电长丝配方的合成方法；2)通过将配方组成与长丝和最终3D打印样品的微观结构相关联，建立结构-加工-性能关系；以及3)表征样品的电子和机械性能，最终用于电子传感平台的设计和制造。总体而言，我们项目的突破潜力在于将3D打印领域的重点从结构考虑转移到功能考虑，即从复杂但被动的建筑转向具有与技术相关的内置设备的建筑。我们的项目还将有助于培养具有独特的多学科材料化学技术和专业技能的高素质科学家，这可以被用于创新的职业生涯。

Electronic devices that are compliant to a variety of form factors is one of the sine qua non conditions for the integration of sensing and optoelectronic technologies in packaging, wearables and connected objects for the Internet of Things. Advances in organic (semi)conducting materials prove that this category of compounds stands as a key player to achieve highly conformable, sustainable, and cost-effective devices. Indeed, the mechanical properties of the organic electronics components can be matched to those of the supporting (soft) substrate and of the targeted object to be laminated with the devices. While developing synthetic and processing strategies to optimize organic electronics compounds in the context of soft and printable devices is a blooming area of research, there is a strong interest in tackling the challenges associated with their monolithic integration within an object. Such integration would eliminate the need for the lamination step and the constraints associated with the mechanical properties of the substrate, leading to the freeform design of self-standing organic electronics devices. In this pan-Canadian collaborative project, we outline our approaches towards the use of organic (semi)conducting materials to prepare three-dimension (3D) printed electronic sensing technologies. While the 2021 Flexible and Printed electronics roadmap mentions that the market size for 3D printed electronics is estimated to reach $1 billion in 2025, it also highlights that it is 'a nascent field'. The scarcity of the investigations on the 3D printing of organic (semi)conducting compounds clearly identifies a gap in fundamental knowledge, to be filled by this research. For instance, conductive filaments made from commodity polymers and carbon nanomaterials for fused deposition modeling are commercially available. However, the use of halogenated solvents in their preparation, along with undisclosed blend composition topped by batch-to-batch variations in conductivity values impedes the establishment of reliable structure-processing-property relationships in the context of sustainable preparation of organic electronic sensing devices.To overcome these challenges, we will capitalize on the synergy of the organic electronics expertise of our team members, respectively in synthesis of vat dyes for organic electronics (Morin), in advanced fabrication (3D printing) and characterization of functional polymer materials (Laventure) and soft semiconductors and transistor sensors design (Rondeau-Gagné). Together, we aim to 1) develop a synthetic approach for an organic electronics semi-conducting solution and an all-polymer conducting filament formulations; 2) establish structure-processing-property relationships by correlating the formulation composition with the microstructure of the filament and that of the resulting 3D printed samples and 3) characterize the electronic and mechanical properties of the samples towards, ultimately, the design and fabrication of an electronic sensing platform. Overall, the breakthrough potential of our project lies in shifting the focus of the 3D printing field from structural to functional considerations, i.e. from complex, yet passive architectures, to architectures with technology-relevant built-in devices. Our project will also contribute to train highly qualified scientists with a unique multidisciplinary technical and professional skillset in materials chemistry, which can be leveraged towards innovative careers.