Tag Archives: Jung Woo Leem

Spider web-like electronics with graphene

A spiderweb-inspired fractal design is used for hemispherical 3D photodetection to replicate the vision system of arthropods. (Sena Huh image)

This image is pretty and I’m pretty sure it’s an illustration and not a real photodetection system. Regardless, an Oct. 21, 2020 news item on Nanowerk describes the research into producing a real 3D hemispheric photodetector for biomedical imaging (Note: A link has been removed),

Purdue University innovators are taking cues from nature to develop 3D photodetectors for biomedical imaging.

The researchers used some architectural features from spider webs to develop the technology. Spider webs typically provide excellent mechanical adaptability and damage-tolerance against various mechanical loads such as storms.

“We employed the unique fractal design of a spider web for the development of deformable and reliable electronics that can seamlessly interface with any 3D curvilinear surface,” said Chi Hwan Lee, a Purdue assistant professor of biomedical engineering and mechanical engineering. “For example, we demonstrated a hemispherical, or dome-shaped, photodetector array that can detect both direction and intensity of incident light at the same time, like the vision system of arthropods such as insects and crustaceans.”

The Purdue technology uses the structural architecture of a spider web that exhibits a repeating pattern. This work is published in Advanced Materials (“Fractal Web Design of a Hemispherical Photodetector Array with Organic-Dye-Sensitized Graphene Hybrid Composites”).

An Oct. 21, 2020 Purdue University news release by Chris Adam, which originated the news item, delves further into the work,

Lee said this provides unique capabilities to distribute externally induced stress throughout the threads according to the effective ratio of spiral and radial dimensions and provides greater extensibility to better dissipate force under stretching. Lee said it also can tolerate minor cuts of the threads while maintaining overall strength and function of the entire web architecture.

“The resulting 3D optoelectronic architectures are particularly attractive for photodetection systems that require a large field of view and wide-angle antireflection, which will be useful for many biomedical and military imaging purposes,” said Muhammad Ashraful Alam, the Jai N. Gupta Professor of Electrical and Computer Engineering.

Alam said the work establishes a platform technology that can integrate a fractal web design with system-level hemispherical electronics and sensors, thereby offering several excellent mechanical adaptability and damage-tolerance against various mechanical loads.

“The assembly technique presented in this work enables deploying 2D deformable electronics in 3D architectures, which may foreshadow new opportunities to better advance the field of 3D electronic and optoelectronic devices,” Lee said.

Here’s a link to and a citation for the paper,

Fractal Web Design of a Hemispherical Photodetector Array with Organic‐Dye‐Sensitized Graphene Hybrid Composites by Eun Kwang Lee, Ratul Kumar Baruah, Jung Woo Leem, Woohyun Park, Bong Hoon Kim, Augustine Urbas, Zahyun Ku, Young L. Kim, Muhammad Ashraful Alam, Chi Hwan Lee. Advanced Materials Volume 32, Issue 46 November 19, 2020 2004456 DOI: https://doi.org/10.1002/adma.202004456 First published online: 12 October 2020

This paper is behind a paywall.

Implanted biosensors could help sports professionals spy on themselves

A May 21, 2020 news item on Nanowerk describes the latest in sports self-monitoring research (or as I like to think of it, spying on yourself),

Researchers from the University of Surrey have revealed their new biodegradable motion sensor – paving the way for implanted nanotechnology that could help future sports professionals better monitor their movements to aid rapid improvements, or help caregivers remotely monitor people living with dementia.

A May 21, 12020 University of Surrey press release (also on EurekAlert), which originated the news item, mentioned the collaboration with a South Korean University and provides a few details about this work,

In a paper published by Nano Energy, a team from Surrey’s Advanced Technology Institute (ATI), in partnership with Kyung Hee University in South Korea, detail how they developed a nano-biomedical motion sensor which can be paired with AI systems to recognise movements of distinct body parts.

The ATI’s technology builds on its previous work around triboelectric nanogenerators (TENG), where researchers used the technology to harness human movements and generate small amounts of electrical energy. Combining the two means self-powered sensors are possible without the need for chemical or wired power sources.

In their new research, the team from the ATI developed a flexible, biodegradable and long-lasting TENG from silk cocoon waste. They used a new alcohol treatment technique, which leads to greater durability for the device, even under harsh or humid environments.

Dr. Bhaskar Dudem, project lead and Research Fellow at the ATI, said: “We are excited to show the world the immense potential of our durable, silk film based nanogenerator. It’s ability to work in severe environments while being able to generate electricity and monitor human movements positions our TENG in a class of its own when it comes to the technology.”

Professor Ravi Silva, Director of the ATI, said: “We are proud of Dr Dudem’s work which is helping the ATI lead the way in developing wearable, flexible, and biocompatible TENGs that efficiently harvest environmental energies. If we are to live in a future where autonomous sensing and detecting of pathogens is important, the ability to create both self-powered and wireless biosensors linked to AI is a significant boost.”

Here’s a link to and a citation for the paper,

Exploring theoretical and experimental optimization towards high-performance triboelectric nanogenerators using microarchitecture silk cocoon films by Bhaskar Dudem, R.D. Ishara G. Dharmasena, Sontyana Adonijah Graham, Jung Woo Leem, Harishkumarreddy Patnam, Anki Reddy Mule, S. Ravi P. Silva, Jae Su Yu. Nano Energy DOI: https://doi.org/10.1016/j.nanoen.2020.104882 Available online 11 May 2020, 104882

This paper is behind a paywall.