RUI: Leaf as a Biodegradable Material for Electronic Components

随着全球家庭收入的持续增长和电子元件的整体成本持续下降，每年生产的电子设备数量达到创纪录的水平以满足需求。然而，这些设备的使用寿命也在下降，因为消费者被每隔几年就会上市的新版本设备所吸引，而制造商的内置过时也会生效。这导致每年产生创纪录数量的电子废物（电子废物）。大部分电子垃圾被丢弃在垃圾填埋场，造成环境污染。一些电子垃圾被送往发展中国家进行回收，那里的工人受到低于标准的健康和安全法规的保护，如果有的话。随着电子垃圾的数量预计将增加到新的水平，这个问题似乎只会变得更糟。在某种程度上帮助解决这个问题的一种方法是用生物来源和可生物降解的材料开发电子设备，这样这些设备就可以在对环境影响最小的情况下被丢弃。美国国家科学基金会的这个项目旨在开发以树叶为基础的电子设备，作为一种环保的、短寿命的传统电子设备的替代品。叶子丰富，有各种纹理和形态。研究人员将研究叶片内部的电荷传输机制以及通过叶片中引入的导电聚合物的电荷传输机制。通过利用这些知识和利用叶片的各种结构，研究人员计划开发各种电子设备，用于收集剩余能量、存储能量和感知周围环境，如叶片内或暴露在叶片中的溶液中的离子含量。研究人员的这项工作将为最终开发一种基于叶子的自供电环境传感器的综合系统奠定基础。PI将指导一个由本科生组成的团队，其中将包括代表性不足的群体成员，以开展研究并实现拟议的项目目标。此外，PI将整合PI最近开发的一门全校范围的研讨会课程的研究成果，该课程侧重于电子发现对文明的影响。在一个电子废物数量不断增加，使用后即扔电子产品的应用越来越多，而这类废物的回收机制明显有限的世界里，有必要开发可生物降解的电子产品，以尽量减少制造过程中对环境的影响，以及在它们被丢弃后。叶子是一种形态多样性丰富的生物材料，因此可以作为活性材料、基质或外壳的一种环保、经济的替代品。研究人员将研究树叶中电子和离子的传输机制，包括树叶在自然状态下和引入导电聚合物时的传输机制。利用这些知识和叶片结构的优势，研究人员将开发电子设备，如用于收集剩余能量的摩擦纳米发电机（teng），用于存储能量的超级电容器，用于环境传感的晶体管和逻辑门，以及基于植物体内水合水平监测的电阻开关机制。这项提议的工作不仅有助于扩大“绿色电子”领域的知识，而且有助于探索在生命系统中开发集成电子产品的潜力，并产生生物启发电子产品的想法。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

As the global household income continues to rise and the overall cost of electronic components continues to fall, a record number of electronic devices are produced every year to satisfy the demand. However, the usable lifetime of these devices has also fallen as consumers are enticed by newer versions of devices that arrive on the market every few years and built-in obsolescence from manufacturers takes effect. This has resulted in the generation of a record amount of electronic waste (e-waste) every year. Most of the e-waste is discarded in landfills which results in environmental pollution. Some e-waste is sent for recycling in the developing world where workers are protected by sub-par health and safety regulations if any. The problem appears to grow only worse as the amount of e-waste is projected to increase to new levels. One way to help address the issue to some extent is to develop electronic devices from materials that are biologically sourced and biodegradable so that these devices can be discarded with minimal environmental impact. This NSF project aims to develop leaf-based electronic devices as an environmentally friendly alternative to conventional electronics with a short lifespan. Leaves are abundant and are available in various textures and morphology. The investigators will study the intrinsic charge transport mechanism within leaves and the charge transport mechanism through the conducting polymers introduced in the leaves. By using this knowledge and taking advantage of the various architecture of the leaves, the investigators plan to develop various electronic devices for harvesting residual energy, storing energy, and sensing the surrounding environment such as ion contents within leaves or in solutions exposed to the leaves. The work to be carried out by the investigators will lay the groundwork for ultimately developing an integrated system of leaf-based self-powered environmental sensors. The PI will mentor a team of undergraduate students which will include members of underrepresented groups to carry out the research and fulfill proposed project goals. In addition, the PI will integrate knowledge gained from the research in a university-wide seminar course that the PI recently developed which focuses on the civilizational consequences of the discoveries in electronics.In a world with an ever-increasing amount of electronic waste, growing applications for use-and-throw electronics, and significantly limited recycling mechanisms for such waste, there is a need to develop biodegradable electronics that minimize environmental impact during fabrication as well as after they are discarded. Leaves are readily available biological materials rich in morphological diversity and therefore could be an environmentally friendly cost-effective alternative as active materials, substrates, or enclosures. The investigators will study electron and ion transport mechanisms in leaves, both in their naturally occurring state and when conducting polymers have been introduced. By using this knowledge and taking advantage of the leaf architecture, the investigators will develop electronic devices such as triboelectric nanogenerators (TENGs) for residual energy harvesting, supercapacitors for storing the energy, transistors and logic gates for environmental sensing, and resistive switching mechanism based in-vivo monitoring of hydration level in plants. The proposed work would not only help expand knowledge in the field of “green electronics” but also help explore the potential for developing electronics integrated within living systems and generate ideas for bio-inspired electronics.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.