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

符合各种形状因素的电子设备是将传感和光电技术集成到物联网的包装、可穿戴设备和连接对象中的必要条件之一。有机（半）导电材料的进展证明，这类化合物是实现高度一致、可持续和具有成本效益的设备的关键因素。实际上，有机电子部件的机械性能可以与支撑（软）基板和待与器件层压的目标物体的机械性能相匹配。虽然开发合成和加工策略以优化有机电子化合物在软和可印刷设备的背景下是一个蓬勃发展的研究领域，但人们对解决与物体内的单片集成相关的挑战有浓厚的兴趣。这样的集成将消除对层压步骤的需要和与基板的机械性能相关联的约束，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，我们概述了我们使用有机（半）导电材料来制备三维（3D）打印电子传感技术的方法。虽然2021年柔性和印刷电子产品路线图提到，3D打印电子产品的市场规模估计将在2025年达到10亿美元，但它也强调这是一个“新兴领域”。对有机（半）导电化合物3D打印的研究的缺乏清楚地表明了基础知识的空白，这项研究将填补这一空白。例如，用于熔融沉积成型的由商品聚合物和碳纳米材料制成的导电丝是市售的。然而，在制备过程中使用卤化溶剂，沿着未公开的共混物组成以及电导率值的批次间变化阻碍了在有机电子传感器件的可持续制备背景下建立可靠的结构-加工-性质关系。为了克服这些挑战，我们将利用团队成员的有机电子专业知识的协同作用，分别用于有机电子用还原染料的合成（Morin）、功能性聚合物材料的先进制造（3D打印）和表征（Laventure）以及软半导体和晶体管传感器设计（Rondeau-Gagné）。我们的目标是：1）开发有机电子半导体溶液和全聚合物导电丝配方的合成方法; 2）通过将制剂组成与长丝的微观结构和所得3D打印样品的微观结构相关联来建立结构-加工-性质关系，以及3）表征样品的电子和机械性质，最终，电子传感平台的设计与制作。总的来说，我们项目的突破性潜力在于将3D打印领域的重点从结构考虑转向功能考虑，即从复杂但被动的架构转向具有技术相关内置设备的架构。我们的项目还将有助于培养高素质的科学家，他们在材料化学方面具有独特的多学科技术和专业技能，可以利用这些技能来实现创新职业。

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.