An alternative nanoscale design for eco-friendly smart glass
"Smart glass," an energy-efficiency product found in newer windows of cars, buildings and airplanes, slowly changes between transparent and tinted at the flip of a switch.
"Slowly" is the operative word; typical smart glass takes several minutes to reach its darkened state, and many cycles between light and dark tend to degrade the tinting quality over time.
Colorado State University chemists have devised a potentially major improvement to both the speed and durability of smart glass by providing a better understanding of how the glass works at the nanoscale.
They offer an alternative nanoscale design for smart glass in new research published June 3 in Proceedings of the National Academy of Sciences. The project started as a grant-writing exercise for graduate student and first author R. Colby Evans, whose idea - and passion for the chemistry of color-changing materials - turned into an experiment involving two types of microscopy and enlisting several collaborators. Evans is advised by Justin Sambur, assistant professor in the Department of Chemistry, who is the paper's senior author.
The smart glass that Evans and colleagues studied is "electrochromic," which works by using a voltage to drive lithium ions into and out of thin, clear films of a material called tungsten oxide. "You can think of it as a battery you can see through," Evans said. Typical tungsten-oxide smart glass panels take 7-12 minutes to transition between clear and tinted.
The researchers specifically studied electrochromic tungsten-oxide nanoparticles, which are 100 times smaller than the width of a human hair. Their experiments revealed that single nanoparticles, by themselves, tint four times faster than films of the same nanoparticles. That's because interfaces between nanoparticles trap lithium ions, slowing down tinting behavior. Over time, these ion traps also degrade the material's performance.
To support their claims, the researchers used bright field transmission microscopy to observe how tungsten-oxide nanoparticles absorb and scatter light. Making sample "smart glass," they varied how much nanoparticle material they placed in their samples and watched how the tinting behaviors changed as more and more nanoparticles came into contact with each other. They then used scanning electron microscopy to obtain higher-resolution images of the length, width and spacing of the nanoparticles, so they could tell, for example, how many particles were clustered together, and how many were spread apart.
Based on their experimental findings, the authors proposed that the performance of smart glass could be improved by making a nanoparticle-based material with optimally spaced particles, to avoid ion-trapping interfaces.
Their imaging technique offers a new method for correlating nanoparticle structure and electrochromic properties; improvement of smart window performance is just one application that could result. Their approach could also guide applied research in batteries, fuel cells, capacitors and sensors.
"Thanks to Colby's work, we have developed a new way to study chemical reactions in nanoparticles, and I expect that we will leverage this new tool to study underlying processes in a wide range of important energy technologies," Sambur said.
The paper's co-authors include Austin Ellingworth, a former Research Experience for Undergraduates student from Winona State University; Christina Cashen, a CSU chemistry graduate student; and Christopher R. Weinberger, a professor in CSU's Department of Mechanical Engineering
LInk to paper: https:/
Anne Manning | EurekAlert!
A human liver cell atlas
15.07.2019 | Max Planck Institute of Immunobiology and Epigenetics
Researchers reveal mechanisms for regulating temperature sensitivity of soil organic matter decompos
15.07.2019 | Chinese Academy of Sciences Headquarters
For some phenomena in quantum many-body physics several competing theories exist. But which of them describes a quantum phenomenon best? A team of researchers from the Technical University of Munich (TUM) and Harvard University in the United States has now successfully deployed artificial neural networks for image analysis of quantum systems.
Is that a dog or a cat? Such a classification is a prime example of machine learning: artificial neural networks can be trained to analyze images by looking...
An international research group led by scientists from the University of Bayreuth has produced a previously unknown material: Rhenium nitride pernitride. Thanks to combining properties that were previously considered incompatible, it looks set to become highly attractive for technological applications. Indeed, it is a super-hard metallic conductor that can withstand extremely high pressures like a diamond. A process now developed in Bayreuth opens up the possibility of producing rhenium nitride pernitride and other technologically interesting materials in sufficiently large quantity for their properties characterisation. The new findings are presented in "Nature Communications".
The possibility of finding a compound that was metallically conductive, super-hard, and ultra-incompressible was long considered unlikely in science. It was...
An interdisciplinary research team at the Technical University of Munich (TUM) has built platinum nanoparticles for catalysis in fuel cells: The new size-optimized catalysts are twice as good as the best process commercially available today.
Fuel cells may well replace batteries as the power source for electric cars. They consume hydrogen, a gas which could be produced for example using surplus...
The fly agaric with its red hat is perhaps the most evocative of the diverse and variously colored mushroom species. Hitherto, the purpose of these colors was...
Physicists at the Max Planck Institute for Nuclear Physics in Heidelberg report the first result of the new Alphatrap experiment. They measured the bound-electron g-factor of highly charged (boron-like) argon ions with unprecedented precision of 9 digits. In comparison with a new highly accurate quantum electrodynamic calculation they found an excellent agreement on a level of 7 digits. This paves the way for sensitive tests of QED in strong fields like precision measurements of the fine structure constant α as well as the detection of possible signatures of new physics. [Physical Review Letters, 27 June 2019]
Quantum electrodynamics (QED) describes the interaction of charged particles with electromagnetic fields and is the most precisely tested physical theory. It...
24.06.2019 | Event News
29.04.2019 | Event News
17.04.2019 | Event News
15.07.2019 | Life Sciences
15.07.2019 | Power and Electrical Engineering
15.07.2019 | Life Sciences