News Release

Engineering a LINC between graphene and polymers

Grant and Award Announcement

University of Pittsburgh

The flexible electronics market was estimated at USD 31.7 billion in 2022 and is projected to almost double to USD 61 billion by 2030, fueled by increasing consumer demand for lighter, more durable, and convenient devices.[i] But greater flexibility comes with economic and production tradeoffs, which is why researchers at the University of Pittsburgh are investigating the potential to grow circuitry like trees in a forest.

Mostafa Bedewy, assistant professor of mechanical engineering and materials science at the Swanson School of Engineering, received a $596,734 Faculty Early Career Development (CAREER) Award from the National Science Foundation to develop LINC – laser-induced nanocarbon – to expedite and revolutionize flexible device manufacturing processes to create graphene and related nanomaterials directly on polymers.

The project continues Bedewy’s work with graphene and related nanocarbons and scalable nanomanufacturing process, which received multiple federally funded grants including an NSF EAGER Award in 2020. The EAGER is a high-risk, high-payoff award that supports potentially transformative work in its early stages, while the CAREER is one of NSF’s most prestigious awards in support of early-career faculty.

“Young faculty like Mostafa are establishing new and intriguing frameworks for advanced manufacturing and optimizing what is possible through computational modeling and exploration at the nanoscale,” noted Brian Gleeson, Harry S. Tack Professor and Chair of Mechanical Engineering and Materials Science. “NSF CAREER awards provide critical funding for young researchers and provide a solid foundation for further fostering advanced research in the Swanson School.”

An electron microscopy image of a Laser-Induced NanoCarbon (LINC) at a magnification of 250 times. It shows how a gradient of laser parameters can be engineered to tailor the morphology and properties of three-dimensional porous graphene-based material used for functional microelectrodes. The moving laser sculpts a seamless transition between an electrically conducting LINC to a more resistive fibrous morphology. Small spikes seen here are a thousand time smaller than a human hair.

Flexing the functionality of polymers and nanocarbons

Biosensors, OLED screens, and photovoltaics, to name a few, are made of polymeric materials like plastic or even fabric. However, current methods for fabricating microelectrodes that allow these devices to function are time consuming, expensive, and sometimes cannot create the desired material, like graphene for example.  

“We want to reach a point where it’s as easy and cheap to make functional microelectrodes as it is to print type in a newspaper,” explained Bedewy, who leads the Swanson School’s NanoProduct Lab. “With our laser-based technology and custom-designed polymers, this becomes a novel fabrication process with the unique ability to locally control the type and surface chemistry of the graphene on-demand.”

Graphene has unique properties that make it a widely used material for flexible device manufacturing; however, the high-heat chemical reactions required to synthesize it destroys the polymer substrate. Another method developed by Bedewy’s lab, chemical vapor deposition (CVD), requires temperatures exceeding 700 degrees Celsius, but again polymers can’t withstand that kind of heat. 

More often, the microelectrodes are printed with graphene ink, or they are produced on a more heat-resistant material, like silicon, and transferred to a polymer, but both methods are slow, expensive, and may fail to create the porous graphene or chemically tailored graphene types that are needed for next generation wearable and implantable biosensors, for example.

An example of Bedewy's bottom-up growth of nanocarbons on a flexible substrate. (NanoProduct Lab)

“Growing” complex nanocarbon patterns on polymer - with the light of a laser

Bedewy’s LINC eliminates the need for this transfer—and the need for graphene ink. Instead, Bedewy uses a molecular-engineered polymer film as the carbon source from which different types and shapes of nanocarbons can then grow like trees in a forest through the use of a controlled laser beam. What’s more, this simplified process allows for simultaneous graphene pattern production on both sides of a film, opening the door for scalable fabrication of complex multilayer devices.

“Traditional methods have limitations at every stage of the process,” said Bedewy. “LINC bypasses many of these limitations so that we can create flexible electronic devices that can’t be printed by typical techniques.”

Another goal of this project is to develop machine learning that can “listen” to the printing process, using real-time acoustic measurements to establish a fundamental understanding of the dynamics at play and further “tune” the manufacturing.

“We’re listening to the process while it’s happening and using the signal to understand and improve the fundamental signs of the process,” explained Bedewy. “Using machine learning is an exciting addition because it can help us refine the process more quickly via computation than repeated trial and error in a lab.”

The five-year project, “CAREER: Laser-Induced Graphene with On-Demand Morphology and Chemistry Control for Flexible Device Manufacturing,” begins on June 1, 2023 and includes support for Bedewy to develop virtual reality educational tools for underserved communities. 

[i] Flexible Electronics Market (By Application: Displays, Sensors, Thin-Film Photovoltaics, Batteries, and Others; By Verticals: Healthcare, Consumer Electronics, Energy & Power, Aerospace, Military, and Others) - Global Industry Analysis, Size, Share, Growth, Trends, Regional Outlook, and Forecast 2022 - 2030. Precedence Research

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