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!
The stacked colour sensor
16.11.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Counterfeits and product piracy can be prevented by security features, such as printed 3-D microstructures
16.11.2017 | Karlsruher Institut für Technologie (KIT)
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
17.11.2017 | Physics and Astronomy
17.11.2017 | Health and Medicine
17.11.2017 | Studies and Analyses