Tech Universe: Monday 25 June

By Miraz Jordan

Scientists at the Australian National University are building a pioneering plasma thruster that could be carrying spacecrafts to the red planet. Photo / Thinkstock
Scientists at the Australian National University are building a pioneering plasma thruster that could be carrying spacecrafts to the red planet. Photo / Thinkstock

A BIG PUSH: At the Australian National University they're building a pioneering plasma thruster that could carry spacecraft to Mars. The Helicon Double Layer Thruster is a tube that contains propellant. Bombarding the tube with 13.56 MHz radio waves turns the propellant inside into plasma, while expelling the charged particles creates thrust. The plasma thruster is very economical with fuel — a typical 5 hour burn uses only 0.8g of propellant. A full-scale test flight should take place by the end of 2014. Advance Australia! Gizmodo details.

RED LIGHT: Solar cells are generally made of silicon or special plastics and harvest visible light. A new kind of cell made of carbon captures the near-infrared part of the spectrum instead, and that's around 40% of the light the sun delivers to us here on Earth. A team from MIT have developed the new cell using carbon nanotubes and buckyballs, but the cells are only a hundredth as efficient as standard cells.

On the other hand, capturing even part of that normally wasted light could be helpful, and the team hope to improve the efficiency considerably. Well, if it's going to waste now it makes sense to start using it. Discovery News has more.

LIGHT LIGHT: Conventional solar cells cost a lot because they need to be thick which uses a lot of highly purified silicon. A team at MIT have a new approach that uses thin layers of silicon etched with a pattern of inverted nanopyramids. Usually thin films of silicon don't absorb light very well but these indentations, each less than a millionth of a metre across, are very efficient at trapping light. A thin wafer of silicon using these nanopyramids is as efficient as a conventional wafer 30 times as thick. That means thinner, lighter, cheaper cells that need less supporting material and cost less to install. The etching can be done easily with standard manufacturing equipment. It makes sense that a bumpy surface would engage more light particles than a smooth one. MIT News explains.

SMOOTH LIGHT: Sony wants to help make smartphone touchscreens less reflective and they're doing it by trapping light with a film. Their low-reflection conductive film has minute, regularly-arranged concave and convex structures on its surface. These structures give the film a uniform reflectance, unlike current touchscreens where the conductive layer can cause streaking because of the ITO sensor electrodes. The overall effect is to make the screen less reflective, displaying a clearer image. It's amazing how bumps can actually smooth something out. Tech On! has further info.

LIGHT AS AIR: Researchers at Aalto University in Finland have a new technique for writing and displaying information on surfaces using only water and air. They fabricated a solid surface with structures in two size scales: microposts that have a size of ten micrometers and tiny nanofilaments that are grown on the posts. A thin layer of air on the surface below water can exist in 2 states that can be changed by using a nozzle to create over- or underpressure in the water. Where the water and air meet there is a striking optical contrast. That means the nozzle can be used to write pixel by pixel on the layer of air, without affecting the solid surface. If the surface is taken out of the water the writing disappears. Now someone needs to figure out a use for underwater writing. Aalto University News elaborates.

Miraz Jordan,

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