Film of self-fused nanowires clear as glass, conducts like metal
A new, ultrathin film that is both transparent and highly conductive to electric current has been produced by a cheap and simple method devised by an international team of nanomaterials researchers from the University of Illinois at Chicago and Korea University.
The film is also bendable and stretchable, offering potential applications in roll-up touchscreen displays, wearable electronics, flexible solar cells and electronic skin. The results are reported in Advanced Functional Materials.
The new film is made of fused silver nanowires, and is produced by spraying the nanowire particles through a tiny jet nozzle at supersonic speed. The result is a film with nearly the electrical conductivity of silver-plate -- and the transparency of glass, says senior author Alexander Yarin, UIC Distinguished Professor of Mechanical Engineering.
"The silver nanowire is a particle, but very long and thin," Yarin said. The nanowires measure about 20 microns long, so four laid end-to-end would span the width of a human hair. But their diameter is a thousand times smaller -- and significantly smaller than the wavelength of visible light, which minimizes light scattering.
The researchers suspended the nanowire particles in water and propelled them by air through a de Laval nozzle, which has the same geometry as a jet engine, but is only a few millimeters in diameter.
"The liquid needs to be atomized so it evaporates in flight," Yarin said. When the nanowires strike the surface they are being applied to at supersonic speed, they fuse together, as their kinetic energy is converted to heat.
"The ideal speed is 400 meters per second," Yarin said. "If the energy is too high, say 600 meters per second, it cuts the wires. If too low, as at 200 meters per second, there's not enough heat to fuse the wires."
The researchers applied the nanowires to flexible plastic films and to three-dimensional objects. "The surface shape doesn't matter," Yarin said.
The transparent flexible film can be bent repeatedly and stretched to seven times its original length and still work, said Sam Yoon, the corresponding author of the study and a professor of mechanical engineering at Korea University.
Earlier this year, Yarin and Yoon and their colleagues produced a transparent conducting film by electroplating a mat of tangled nanofiber with copper. Compared to that film, the self-fused silver nanowire film offers better scalability and production rate, Yoon said.
"It should be easier and cheaper to fabricate, as it's a one-step versus a two-step process," said Yarin. "You can do it roll-to-roll on an industrial line, continuously."
Co-authors with Yarin and Yoon are Jong-Gun Lee, Do-Yeon Kim, Jong-Hyuk Lee and Donghwan Kim of Korea University; Suman Sinha-Ray of the Indian Institute of Technology in Indore, India; and Mark T. Swihart of the State University of New York at Buffalo.
The research was supported by the National Research Foundation, GFHIM-2013M3A6B1078879, and the Industrial Strategic Technology Development Program, 10045221, funded by the Ministry of Knowledge Economy of Korea.
Bill Burton | EurekAlert!
Let the good tubes roll
19.01.2018 | DOE/Pacific Northwest National Laboratory
Method uses DNA, nanoparticles and lithography to make optically active structures
19.01.2018 | Northwestern University
On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.
We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
19.01.2018 | Materials Sciences
19.01.2018 | Health and Medicine
19.01.2018 | Physics and Astronomy