Tag Archives: electronics

Harvesting Clean Hydrogen Fuel Through Artificial Photosynthesis

A new, stable artificial photosynthesis device doubles the efficiency of harnessing sunlight to break apart both fresh and salt water, generating hydrogen that can then be used in fuel cells.

The device could also be reconfigured to turn carbon dioxide back into fuel.

Hydrogen is the cleanest-burning fuel, with water as its only emission. But hydrogen production is not always environmentally friendly. Conventional methods require natural gas or electrical power. The method advanced by the new device, called direct solar water splitting, only uses water and light from the sun.

If we can directly store solar energy as a chemical fuel, like what nature does with photosynthesis, we could solve a fundamental challenge of renewable energy,” said Zetian Mi, a professor of electrical and computer engineering at the University of Michigan who led the research while at McGill University in Montreal.

Faqrul Alam Chowdhury, a doctoral student in electrical and computer engineering at McGill, said the problem with solar cells is that they cannot store electricity without batteries, which have a high overall cost and limited life.

The device is made from the same widely used materials as solar cells and other electronics, including silicon and gallium nitride (often found in LEDs). With an industry-ready design that operates with just sunlight and seawater, the device paves the way for large-scale production of clean hydrogen fuel.

Previous direct solar water splitters have achieved a little more than 1 percent stable solar-to-hydrogen efficiency in fresh or saltwater. Other approaches suffer from the use of costly, inefficient or unstable materials, such as titanium dioxide, that also might involve adding highly acidic solutions to reach higher efficiencies. Mi and his team, however, achieved more than 3 percent solar-to-hydrogen efficiency.

Source: https://news.umich.edu/

Non-toxic Virus Quickly Dissipate Heat From Electronic Devices

The researcher team of Tokyo Tech discovered that the film constructed by assembling a nontoxic filamentous virus functions as a heat dissipation material, and that can be simply prepared by drying the virus aqueous solution at room temperature. This discovery is expected to elucidate the mechanism of new heat transport in electronics.

Organic polymeric materials generally have low thermal conductivity and are not suitable for rapid heat dissipation of electric and electronic equipment in the past. In order to improve its thermal conductivity, it has been considered effective to heat transfer through a covalent bond by “orientation processing” in which molecules are aligned in the same direction, or to composite with an inorganic material.

A research team led by Assistant Professor Toshiki Sawada and Professor Takeshi Serizawa is focusing on the capability to form regularly assembled structures in a wide scale from nano to macro (so called hierarchical assembly) observed in the natural systems and the hierarchically assembled structures prepared in this way, the phenomenon where molecules accumulate around the perimeter as an aqueous solution in which molecules are dissolved evaporates (coffee ring effect) was utilized to assemble a filamentous virus for the film preparation. As a result, it was found that the thermal diffusivity at the edge of the film drastically enhanced to a value comparable to that of inorganic glass, and that facilitates the utilization of the hierarchically assembled biomacromolecule. This helps future development of electric and electronic devices composed of not only viruses but also various naturally derived molecules.

(a) Phage and (b) hexagonally assembled structures of the phages in the film.

Until now, orientation processing and compositing with inorganic materials have been considered effective for the high thermal conductivity of organic polymeric materials. However, since this virus film can be prepared by evaporating an aqueous solution of a filamentous virus at room temperature, it is expected to lead to the establishment of a method for easily constructing heat dissipation materials under mild conditions that do not require special operations.

Source: https://www.titech.ac.jp/