AZoM interviews Seokheun Choi, a professor in the Department of Electrical and Computer Engineering at the State University of New York. His new research details the production of a prototype circuit board printed on a sheet of paper.
Can you please introduce yourself, describe your professional background and how you came to be involved in electronic innovation?
My long-term goal is to create green and renewable electronic systems and advance their potential for translation into practical, real-world disposable Internet of Things (IoT) applications. Papertronic’s current work is the logical next step for ideas and observations made in my previous work with paper-based biobatteries, and is part of a recent mission to create a self-powered biosensing system based on of paper. My work on papertronics, paperfluidics, flexible electronics and green electronics has focused on the design of integrated papertronics for real applications. I am one of the few pioneers in research on paper-based biobatteries and papertronics, and have recently published major reviews of the full range of paper-based batteries and their applications.
How big is the e-waste problem? Why is it so hard to recycle?
As electronics become more and more ubiquitous and rapid updates lead to rapid obsolescence, electronic waste is increasing enormously, developing serious negative effects on the environment and public health. The United States generated about 7 million tons of e-waste in 2019, of which only about 17% was recycled. It is very difficult to recycle electronic devices because they are not technically designed to be recycled and have non-biodegradable and toxic inorganic materials.
You have created a prototype circuit board on a sheet of paper. How is it possible?
The paper has superior compatibility with single-use applications, providing a more affordable, readily available, flexible and easily disposable alternative. The biodegradability of paper has attracted a lot of attention as the future of green electronics, reducing the dramatic increase in e-waste. Moreover, due to its excellent mechanical and dielectric properties with chemical and thermal stability, paper has become a revolutionary substrate for next-generation electronics, known as papertronics.
Image credit: Seokheun Choi
Paper’s natural compatibility with wicking, printing and stacking has allowed us to minimize manufacturing processes and device design complexity by exploiting all the beneficial properties of paper in a cost-effective and environmentally friendly way. the environment. Through wax printing, paper ink injection and screen printing, the metallic threads were able to retain their flexibility while achieving full integration with the paper substrate.
What potential future applications could these paper-based electronic devices support?
The papertronics will be adapted to disposable wireless sensor networks (WSN) via the Internet of Things, named the Internet of Disposable Things (IoDT). The novelty of the IoDT is that its WSNs can be built with small, compact, disposable, functional, but inexpensive boxes that can connect until the job is done and then be easily discarded. IoDT devices will provide a high degree of intelligence and autonomy by enabling the rapid deployment of new applications and the creation of affordable services, such as personalized point-of-care healthcare systems, logistics solutions and tracking shipments, food and groceries. surveillance systems and military surveillance or delivery systems.
What is the innovation of this research and what is the most significant or exciting part for you?
Even the latest attempts to use paper for electronics have gone no further than conceptual research and failed to secure its potential for translation into practical, real-world applications. Paper could only be used as a substrate for mounting off-the-shelf, off-the-shelf, non-paper electronic components, precluding an entirely paper-based device platform, making it difficult to fully recycle and elimination of environmental footprints.
We provided a completely paper-based device with all paper components on a paper printed circuit board. In particular, a methodology was discussed to simultaneously realize highly tunable resistors, supercapacitors and electrolyte field effect transistors on and within the thickness of a single sheet of paper. Each electronic component was completely embedded in functionalized paper regions and exhibited favorable electrical activity, adaptability, flexibility, and disposable.
How do these papertonics perform compared to traditional electronics?
Do you think these paper-based electronic devices could completely replace traditional electronics in the future? The goal of this project was not to replace the conventional inorganic-based electronics industry. On the contrary, it offered opportunities for new techniques, applications and markets in order to reduce the dramatic increase in electronic waste. Disposable single-use operation for a short scheduled period will not require high-tech integrated circuits with high resolution and reliability. However, more research work for higher density and performance will be done.
What other materials are used in these paper-based electronic devices?
Since biodegradable electronics made from fully biodegradable materials will solve the uncontrollable problem of electronic waste, intensive technological advances in materials science and processing with paper will be essential. Although the project attempted to use biocompatible synthetic polymers and environmentally friendly semiconductor, conductive and insulating materials, the discovery and engineering of biodegradable materials was outside the scope of this project. The objective of this work was to understand the potential of paper as a substrate and establish an innovative strategy to integrate existing electronic components into paper and develop the manufacturing paradigm. However, the ingredients will be replaced with more biodegradable materials in future work.
How to dispose of these circuit boards? Are there any harmful by-products?
Our all-paper device for single-use applications can be easily and safely disposed of by incineration or biodegradation. We showed that our paper circuit boards were reduced to ashes 20 s after ignition. Some by-products are generated which can be harmful to the environment. However, if devices can be disposed of only by incineration, we can significantly reduce e-waste. Incineration facilities can incorporate many techniques to ensure adequate combustion and reduce emissions.
What limitations must be overcome before this technology can be scaled?
Additional packaging will be required for all paper-based devices, as moisture can significantly alter the morphology of the paper and degrade its performance and shelf life. Additionally, some potential exposure of the paper to other microorganisms can biodegrade the paper through their enzymatic activities.
Where can readers find more information?
1. M. Landers, A. Elhadad, M. Rezaie, and S. Choi, “Integrated Papertronics Techniques: Highly Customizable Resistor, Supercapacitor, and Transistor Circuits on a Single Sheet of Paper,” ACS Applied Materials & Interfaces, 14 , 45658 -45668, 2022 https://pubs.acs.org/doi/10.1021/acsami.2c13503
2. S. Choi, “Electrogenic Bacteria Promise New Opportunities for Powering, Sensing, and Synthesizing”, Small, review article, 18 (18), 2107902, 2022 https://onlinelibrary.wiley.com/doi/abs/10.1002 / small.202107902
3. Y. Gao and S. Choi, “Stepping Towards Self-powered Papertronics: Integrating Biobatteries into a Single Sheet of Paper”, Advanced Materials Technologies, 2, 1600194, 2017 https://onlinelibrary.wiley.com/doi/abs /10.1002/admt.201600194
About Seokheun Choi
Seokheun “Sean” Choi is a professor in the Department of Electrical and Computer Engineering at the State University of New York (SUNY) in Binghamton. Currently, he leads “Bioelectronics & Microsystems Lab” and “Center for Research in Advanced Sensing Technologies & Environmental Sustainability” as director. His current research focuses on the next generation of “electronics, sensors and energy technologies”, including self-powered electronics, wearable and expandable sensors, biobatteries, papertronics and fibertronics. Over the years, he has secured over $4 million in funding from the NSF, ONR, and SUNY Research Foundation. He is the author of over 150 journal and conference articles, two book chapters and one book, and holds two US patents. For more information, feel free to visit his research website, http://ws.binghamton.edu/choi/.