Harvesting unexploited energy in the living environment is increasingly becoming an intense research area as the global push to replace fossil fuels with clean and renewable energy sources heats up. There is an almost infinite number of mechanical energy sources all around us - basically, anything that moves can be harvested for energy. This ranges from the very large, like wave power in the oceans, to the very small like rain drops or biomechanical energy from heart beat, breathing, and blood flow. In an intriguing demonstration, researchers at Georgia Tech have now demonstrated that the technology offered by nanogenerators can also be used for large-scale energy harvesting.
The low-frequency fluctuations in electrical current attract particular attention among researchers. The low-frequency electronic 1/f noise was first discovered in vacuum tubes, in 1925, and later observed in a wide variety of electronic materials and devices. The importance of this noise for electronic and communication devices motivated numerous studies of its physical mechanisms and methods for its control. Researchers were now able to shed light on 1/f noise origin and mechanisms using a set of multi-layered graphene samples with the thickness continuously varied from around 15 atomic planes to a single layer of graphene.
The coming age of wearable, highly flexible and transparent electronic devices will rely on essentially invisible electronic and optoelectronic circuits. In order to have close to invisible circuitry, one must have optically transparent thin-film transistors. In order to have flexibility, one needs bendable substrates. Researchers have now now fabricated transistors on specially designed nanopaper. They show that flexible organic field-effect transistors (OFETs) with high transparency and excellent mechanical properties can be fabricated on tailored nanopapers.
A bacterium which causes disease reacts to the antibiotics used as treatment by becoming resistant to them, sooner or later. This natural process of adaptation, antimicrobial resistance, means that the effective lifespan of antibiotics is limited. Unnecessary use and inappropriate use of antibiotics favors the emergence and spread of resistant bacteria. New research uses a graphene-based photothermal agent to trap and kill bacteria.
The purpose of the emerging field of nanotoxicity is to recognize and evaluate the hazards and risks of engineered nanomaterials and evaluate safety. Today, we don't even know what the impact of most chemicals is, and that includes products that have been produced by industry for many years. Nevertheless, a general understanding about nanotoxicity is slowly emerging as the body of research on cytotoxicity, genotoxicity, and ecotoxicity of nanomaterials grows. A new review summarizes and discusses recent reports derived from cell lines or animal models concerning the effects of nanomaterials on, and their application in, the endocrine system of mammalian and other species.
As the semiconductor industry has shrunk the size of transistors they have also had to shrink the size of the masks that define them. Billions of dollars has gone into new technologies to lithographically pattern and define them. Defining these tiny masks has been one of the most difficult parts of making smaller and smaller transistors and a novel nanofabrication approach uniquely side-steps this problem. Researchers at the Kavli Nanoscience Institute have come up with a novel method to three-dimensionally sculpt silicon nanostructures that is easily integrable with existing massively parallel fabrication.
Carbon nanotubes, like the nervous cells of our brain, are excellent electrical signal conductors and can form intimate mechanical contacts with cellular membranes, thereby establishing a functional link to neuronal structures. There is a growing body of research on using nanomaterials in neural engineering. Carbon nanotube (CNT) synapse circuits are a first step in this direction. In new work, researchers at the University of California, Los Angeles, have developed a CNT synapse with the elementary dynamic logic, learning, and memory functions of a biological synapse.
Quantum dots are expected to deliver lower cost, higher energy efficiency and greater wavelength control for a wide range of products, including lamps, displays and photovoltaics. Unfortunately, the toxicity of the elements used for efficient quantum dot based LEDs is a severe drawback for many applications. Therefore, light-emitting devices which are based on the non-toxic element silicon are extraordinary promising candidates for future QD-lighting applications. Researchers have now demonstrated highly efficient and widely color-tunable silicon light-emitting diodes (SiLEDs). The emission wavelength of the devices can easily be tuned from the deep red (680 nm) down to the orange/yellow (625 nm) spectral region by simply changing the size of the used size-separated silicon nanocrystals.