Stretchable, flexible, wearable solar cells take top prize at Research Expo 2016

wearable solar cells
This year's Research Expo winners. Photo: Erik Jepsen/UC San Diego Publication

Solar cells that are stretchable, flexible and wearable won the day and the best poster award from a pool of 215 at Research Expo 2016 April 14 at the University of California San Diego. The winning nanoengineering researchers aim to manufacture small, flexible devices that can power watches, LEDs and wearable sensors. The ultimate goal is to design and build much bigger flexible solar cells that could be used as power sources and shelter in natural disasters and other emergencies.

Research Expo is an annual showcase of top graduate research projects for the Jacobs School of Engineering at UC San Diego. During the poster session, graduate students are judged on the quality of their work and how well they articulate the significance of their research to society. Judges from industry, who often are alumni, pick the winners for each department. A group of faculty judges picks the overall winner from the six department winners.

This year, in addition to solar cells, judges recognized efforts to develop 3D skeletal muscle on a chip; a better way to alleviate congestion in data center networks; a nano-scale all-optical sensor; fiber optic strain sensors for structural health monitoring; and a way to predict earthquake damage in freestanding structural systems.

Students are chosen both for the quality of their research and their ability to communicate their work clearly, said George Tynan, associate dean of the Jacobs School of Engineering at UC San Diego. “It’s not enough to have great ideas and great solutions,” he said. “You have to be able to communicate the impact of your work.”

Timothy O’Connor, a nanoengineering Ph.D. student in the research group of professor Darren Lipomi, and winner of the overall best poster award, certainly did that during an interview after the poster sessions. “The greatest challenge of our time is the way that we acquire and distribute energy,” he said. “I honestly believe that if the human race doesn’t get a grip on the way in which we do this, we’re going to play the end game for all of us.”

O’Connor is part of a team of researchers in Lipomi’s lab that is working to create extremely cheap but still efficient solar cells that can be printed roll-to-roll, much like a newspaper, and can easily be deployed on everything from solar farms, to buildings, to clothes and even the human body.

To make the solar cells, O’Connor first needed to determine the best recipe to get optimal electronic performance and flexibility in the same material. He and colleagues discovered a series of rules for molecular design that allowed them to develop solar cells capable of producing 1000 microWatts of power over more than 1000 cycles. That is enough to power a digital watch and LEDs, as well as other wearable biomedical devices. By contrast, the lab’s previous version of these cells could only function for five to 10 cycles.

Next steps include producing much larger versions of the cells, which could be used both as shelters and power sources. “You can deploy these solar tarps and provide a canopy, which would protect people from the elements, while at the same time absorbing sunlight and providing power to any electronic equipment below,” O’Connor said. Researchers also are exploring sustainable manufacturing approaches, such as using water as a substrate to print the cells on. “Green chemistry is definitely a focus for us,” O’Connor said.

O’Connor’s Research Expo poster can be found here:
STRETCHABLE AND ULTRA-FLEXIBLE ELECTRONICS: WEARABLE SOLAR CELLS
Student(s): Timothy Francis Oconnor
Professor(s): Darren J. Lipomi
Industry Application Area(s): Energy/Clean technology | Materials | Semiconductor

Other departmental winners were:

Bioengineering Best Poster:
ENGINEERED 3D SKELETAL MUSCLE-ON-A-CHIP AS AN IN VITRO TOOL
Student(s): Gaurav Agrawal
Professor(s): Shyni Varghese
Industry Application Area(s): Life Sciences/Medical Devices & Instruments

Computer Science and Engineering Best Poster:
FIBBING TO ALLEVIATE CONGESTION IN WAN AND DATA CENTER NETWORKS
Student(s): Ashish Kashinath | Justin Tee | Debjit Roy
Professor(s): George M. Porter
Industry Application Area(s): Internet, Networking, Systems | Software, Analytics

Electrical and Computer Engineering Best Poster:
PLASMONIC NANOSTRUCTURES FOR NANO-SCALE SENSING: PATH TO AN ALL-OPTICAL INTEGRATED SENSOR
Student(s): Ashok Kodigala
Professor(s): Boubacar Kante | Y. Shaya Fainman
Industry Application Area(s): Electronics/Photonics | Materials | Semiconductor

Katie Osterday Best Poster Award Mechanical and Aerospace Engine:
EVALUATION OF FIBER OPTIC STRAIN SENSORS FOR APPLICATIONS IN STRUCTURAL HEALTH MONITORING
Student(s): Benjamin Levi Martins
Professor(s): John B. Kosmatka
Industry Application Area(s): Aerospace, Defense, Security | Civil/Structural Engineering | Energy/Clean technology

Structural Engineering Best Poster:
EXPERIMENTAL AND NUMERICAL STUDIES OF FREESTANDING STRUCTURAL SYSTEMS
Student(s): Christine Wittich
Professor(s): Tara C. Hutchinson
Industry Application Area(s): Civil/Structural Engineering