Researchers at Rensselaer Polytechnic Institute have developed a new, ultra-simple method for making layers of gold that measure only billionths of a meter thick. The process, which requires no sophisticated equipment and works on nearly any surface including silicon wafers, could have important implications for nanoelectronics and semiconductor manufacturing.
Sang-Kee Eah, assistant professor in the Department of Physics, Applied Physics, and Astronomy at Rensselaer, and graduate student Matthew N. Martin infused liquid toluene — a common industrial solvent – with gold nanoparticles. The nanoparticles form a flat, closely packed layer of gold on the surface of the liquid where it meets air. By putting a droplet of this gold-infused liquid on a surface, and waiting for the toluene to evaporate, the researchers were able to successfully coat many different surfaces – including a 3-inch silicon wafer — with a monolayer of gold nanoparticles.
“There has been tremendous progress in recent years in the chemical syntheses of colloidal nanoparticles. However, fabricating a monolayer film of nanoparticles that is spatially uniform at all length scales — from nanometers to millimeters — still proves to be quite a challenge,” Eah said. “We hope our new ultra-simple method for creating monolayers will inspire the imagination of other scientists and engineers for ever-widening applications of gold nanoparticles.”
Watch a video demonstration of this new fabrication process at: http://www.youtube.com/watch?v=nqkwM9o1s-w
Results of the study, titled “Charged gold nanoparticles in non-polar solvents: 10-min synthesis and 2-D self-assembly,” were published recently in the journal Langmuir. Read the journal paper at: http://dx.doi.org/10.1021/la100591h
Whereas other synthesis methods take several hours, this new method chemically synthesizes gold nanoparticles in only 10 minutes without the need for any post-synthesis cleaning, Eah said. In addition, gold nanoparticles created this way have the special property of being charged on non-polar solvents for 2-D self-assembly.
Previously, the 2-D self-assembly of gold nanoparticles in a toluene droplet was reported with excess ligands, which slows down and complicates the self-assembly process. This required the non-volatile excess ligands to be removed in a vacuum. In contrast, Eah’s new method ensures that gold nanoparticles float to the surface of the toluene drop in less than one second, without the need for a vacuum. It then takes only a few minutes for the toluene droplet to evaporate and leave behind the gold monoloayer.
“The extension of this droplet 2-D self-assembly method to other kinds of nanoparticles, such as magnetic and semiconducting particles, is challenging but holds much potential,” Eah said. “Monolayer films of magnetic nanoparticles, for instance, are important for magnetic data storage applications. Our new method may be able to help inform new and exciting applications.”
Co-authors on the paper are former Rensselaer undergraduate researchers James I. Basham ’07, who is now a graduate student at Pennsylvania State University, and Paul Chando ’09, who will begin graduate study in the fall at the City College of New York.
The research project was supported by Rensselaer, the Rensselaer Summer Undergraduate Research Program, the National Science Foundation (NSF) Research Experiences for Undergraduates, and the NSF’s East Asia and Pacific Summer Institutes and Japan Society for the Promotion of Science.
For more information, visit Eah’s website at: http://www.rpi.edu/~eahs.Published June 16, 2010 Contact: Michael Mullaney
Michael Mullaney | EurekAlert!
Intelligent wheelchairs, predictive prostheses
20.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Jelly with memory – predicting the leveling of com-mercial paints
15.12.2017 | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale
Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...
For photographers and scientists, lenses are lifesavers. They reflect and refract light, making possible the imaging systems that drive discovery through the microscope and preserve history through cameras.
But today's glass-based lenses are bulky and resist miniaturization. Next-generation technologies, such as ultrathin cameras or tiny microscopes, require...
Scientists from the University of Zurich have succeeded for the first time in tracking individual stem cells and their neuronal progeny over months within the intact adult brain. This study sheds light on how new neurons are produced throughout life.
The generation of new nerve cells was once thought to taper off at the end of embryonic development. However, recent research has shown that the adult brain...
Theoretical physicists propose to use negative interference to control heat flow in quantum devices. Study published in Physical Review Letters
Quantum computer parts are sensitive and need to be cooled to very low temperatures. Their tiny size makes them particularly susceptible to a temperature...
Let’s say the armrest is broken in your vintage car. As things stand, you would need a lot of luck and persistence to find the right spare part. But in the world of Industrie 4.0 and production with batch sizes of one, you can simply scan the armrest and print it out. This is made possible by the first ever 3D scanner capable of working autonomously and in real time. The autonomous scanning system will be on display at the Hannover Messe Preview on February 6 and at the Hannover Messe proper from April 23 to 27, 2018 (Hall 6, Booth A30).
Part of the charm of vintage cars is that they stopped making them long ago, so it is special when you do see one out on the roads. If something breaks or...
15.02.2018 | Event News
13.02.2018 | Event News
12.02.2018 | Event News
16.02.2018 | Information Technology
16.02.2018 | Health and Medicine
16.02.2018 | Physics and Astronomy