- Education & Outreach
- Roll-to-Roll Fabrication and Processing Facility
- Nanoimprint Lithography & Hybrid Coating R2R Coaters
- Conte Nanotechnology Cleanroom Lab
- Nuclear Magnetic Resonance Facility
- UMass-Amherst Mass Spectrometry Center
- UMass Amherst Electron Microscopy Center
- Hysitron Triboindenter
- Nanonex Nanoimprinter
<?xml version="1.0" encoding="UTF-8"?> Self-made DNA scaffold could make the production of single-electron devices far more scalable Illustration: Nanoscience Center/University of Jyväskylä and BioMediTech/University of Tampere To organize nanoparticles into structures that are useful in electronics, researchers have turned to DNA scaffolds that self-assemble into patterns and attract the nanoparticles into functional arrangements. Now researchers at the Nanoscience Center (NSC) of the University of Jyväskylä and BioMediTech (BMT) of the University of Tampere, both in Finland, have used these DNA scaffolds to organize three gold nanoparticles into a single-electron transistor. DNA scaffolds have previously been used to organize gold nanoparticles into patterns. But this work represents the first time that these DNA scaffolds have been used to construct precise, controllable DNA-based assemblies that are fully electrically characterized for use in single-electron nanoelectronics. The immediate benefit: There’s no longer a need to keep these structures at cryogenic temperatures in order for them to work. The way that electron transport occurs in single-electron devices is altogether different than in conventional electronics. With single-electron devices, the electron is governed by quantum mechanics. In these devices, there is what is known as an “island” where electrons are contained and isolated by tunnel junctions that control electron tunneling. The tunnel junctions operate under the quantum mechanical phenomenon known as the Coulomb Blockade, in which electrons inside the device produce a strong repulsion preventing other electrons from circulating. The Finland-based scientists observed a clear Coulomb Blockade phenomenon with their device—all the way up to room temperature. While this is not the first time that Coulomb Blockade has been observed at temperatures that high, its demonstration in a single-electron device should prove significant for these devices. But, more importantly, the use of a self-assembling DNA scaffold could make the production of these devices far more scalable. “Such a device based on DNA self-assembly would be a vast improvement due to fully parallel fabrication easily scaled for mass-production, which is the property not possible with previous methods demonstrating Coulomb Blockade up to room temperature,” explained Jussi Toppari, a Senior Lecturer at the NSC and a member of the research team, in an e-mail interview with IEEE Spectrum. In research described in the journal Nano Letters , the researchers fabricated a single-electron transistor (SET) that can visualize the effect of single electrons leaving or arriving to the islands of the device via tunneling. “The device was electrically characterized and proven to work at a basic level,” says Toppari. “However, gate dependency could not be fully demonstrated due to technical reasons. A fully working device could be utilized as a transistor or an extremely sensitive electrometer at the nanoscale.” Of course, realizing a full-fledged single-electron device is still going to require some substantial efforts. The main sticking point preventing the full utilization of this method for builing single electron nanoelectronic circuits is the difficulty associated with growing gold nanoparticles, says Toppari. “Otherwise only the DNA-self-assembly sets the limits, and those have been pushed very far already.”
RIT engineering faculty awarded NSF grant for high-tech nanofabrication equipment - EurekAlert (press release)
RIT engineering faculty awarded NSF grant for high-tech nanofabrication equipmentEurekAlert (press release)Jing Zhang, engineering faculty member at Rochester Institute of Technology, received a $305,000 grant from the National Science Foundation to acquire a new etching system for photonic, electronic and bio-device fabrication. The system strengthens RIT ...and more »
Scientists have created hybrid perovskite-graphene solar cells that show good stability upon exposure to sunlight, while still maintaining efficiency over 18% - the highest reported efficiency of...
<?xml version="1.0" encoding="UTF-8"?> Fractals and biomimetics just helped to surpass the performance of today’s transparent electrode materials Image: M. Giersig/HZB If you take a close look at a leaf from a tree and you’ll notice the veins that run through it. The structure these veins take are what’s called a quasi-fractal hierarchical networks. Fractals are geometric shapes in which each part has the same statistical character of the whole. Fractal science is used to model everything from snowflakes and the veins of leaves to crystal growth. Now an international team of researchers led by Helmholtz-Zentrum Berlin have mimicked leaves’ quasi-fractal structure and used it to create a network of nanowires for solar cells and touch screen displays. Indium tin oxide (ITO) has been the go-to material for transparent conductors in displays and solar cells. While the costs associated with ITO have been one of the main knocks against it, it’s been difficult for the various nanomaterials proposed as alternatives to replace it. Nanomaterials—including silver nanowires, carbon nanotubes and graphene—have not only been handicapped by their own relative high costs, but their performance has been somewhat lacking as well. With this new method of distribution, nanowires are able to surpass the performance of traditional ITO layers. The reason for this becomes a little clearer when you go back and look at the leaf. The distribution of veins in the leaf is determined in part by the amount of shade and sunlight the leaf receives. With ITO, the material is spread out in one continuous, uniform film. However, the way the sunlight strikes a solar cell or the way a finger presses on a touch-screen display are not uniform. This reduces the ITO layer’s efficiency. In research described in the journal Nature Communications , the international research team used a quasi-fractal hierarchical network to optimize the distribution of the nanowires on a solar cell according to three conditions: provide maximum surface coverage, achieve a uniform current density, and have a minimal overall resistance. “On the basis of our studies, we were able to develop an economical transparent metal electrode," Michael Giersig, a professor at Helmholtz-Zentrum Berlin and who led the research, said in a press release. “We obtain this by integrating two silver networks. One silver network is applied with a broad mesh spacing between the micron-diameter main conductors that serve as the ‘highway’ for electrons transporting electrical current over macroscopic distances.” Next to this broad highway for the electrons, the researchers added randomly distributed nanowire networks that serve as local conductors to cover the surface between the large mesh elements. “These smaller networks act as regional roadways beside the highways to randomize the directions and strengths of the local currents, and also create refraction effects to improve transparency,” according to Giersig. Solar cells with the leaf-vein network had an efficiency of 5.91 percent in experiments. Those with a standard ITO had 5.37 percent.
A transparent flexible thin-film triboelectric nanogenerator for scalable electricity generationGuang Zhu; Xiao Yan Wei; Zhong Lin WangInternational Journal of Nanomanufacturing, Vol. 12, No. 3/4 (2016) pp. 396 - 403We report a flexible thin-film-based triboelectric nanogenerator (TF-TENG) that has a one-component laminated structure as thin as 100 µm. The electricity-generating process of the TF-TENG takes advantage of the interaction between the TF-TENG and an external object that carries triboelectric charge on the surface. The motion of the object creates electric potential difference between two electrodes on the TF-TENG, which then produces electron flow in the external circuit. When triggered by foot stomping, a TF-TENG (20 cm by 20 cm) spread on the floor could generate an open-circuit voltage of 700 V, a short-circuit current of 3 mA, and an instantaneous power of 168 mW that corresponds to a power density of 4.2 W/m<SUP align="right">2</SUP>. The generated electricity could simultaneously power 1,000 LEDs. The TF-TENG can be tailored to any desired size and shape that are suitable in a variety of circumstances as long as contacts with external objects take place. When the TF-TENG is scaled up in area and used in places that have large flows of people such as subway stations and shopping malls, the produced electric energy in total may become considerable.
Ambitious, complex research that leads to breakthrough discoveries requires large-scale, long-term investments. Today, the National Science Foundation (NSF) announces $94 million in funding to support four new Science and Technology Centers (STCs), partnerships that lay the foundations for advances in fields ranging from cell biology and mechanobiology to particle physics and materials science. Each awardee will receive up to $24 million over a five-year period, with the possibility ... More at http://www.nsf.gov/news/news_summ.jsp?cntn_id=189782&WT.mc_id=USNSF_51&WT.mc_ev=click This is an NSF News item.