A cheap nanowire ink that can boost existing solar cell efficiency by 25%

A cheap nanowire ink that can boost existing solar cell efficiency by 25%

• By Sebastian Anthony on April 10, 2013 at 6:41 am
• 6 Comments

Share This Article

4
inShare

Sol Voltaics, a Swedish startup founded by nanotech master Lars Samuelson, has announced its first product: Solink — an ink made from nanowires that, when slathered onto existing solar panels, can boost efficiency by 25%. Not only could this give solar power the efficiency boost needed to compete with other energy sources, such as fossil fuels, but the method in which the ink is created is also very exciting.

Solink, which is added to conventional solar cells towards the end of the production process, is an additive that contains galium arsenide (GaAs) nanowires. As we’ve covered in the past, galium arsenide is one of most efficient photovoltaic materials out there — but it’s much more expensive than silicon. In essence, Sol Voltaics, building on advances made by Lars Samuelson’s research group at Lund University in Sweden, has found a way of cheaply producing large quantities of galium arsenide nanowires, and then producing an ink that is easy to apply to existing solar cells.

Lund University nanowires produced using aerotaxy

We have known for some time that nanowires, due to their long length, can bemuch more efficient than normal, flat semiconductors (light bounces back and forth along their length, increasing absorption). The problem, though, is that producing nanowires is generally a slow, expensive, substrate-based epitaxial process that’s similar to the production of conventional silicon chips. Late last year, however, Lund University announced that it had succeeded in creating self-assembling nanowires — galium arsenide nanowires that can be produced in the gas phase without a substrate, accelerating the production of nanowires by 1,000 times.

To do this, nanoparticles of gold are pumped through a tube-shaped furnace. By adding the gases TMGA (trimethylgallium) and AsH3 (arsine) to the furnace, gallium and arsenide are deposited onto the crystal, creating a nanowire (pictured below). For more details on this process, see our story detailing Lund University’s breakthrough. This process, called aerotaxy, is exciting because it’s incredibly fast, efficient, is a continuous process, and might eventually be applicable to the production of computer chips.

All told, Sol Voltaics says that it needs just one gram of nanowires to increase the efficiency of a one-square-meter crystalline silicon solar panel by 25%. Speaking to Technology Review, Sol Voltaics’ CEO says that Solink should increase production costs by one or two cents per watt — and the current cost of producing solar cells is now below 75 cents per watt. In short, we’re talking about a huge efficiency boost for just a tiny increase in cost.

Sol Voltaics has secured $11 million in funding so far, and expects to need $50 million to begin commercial production of Solink in 2015.

Now read: MIT creates solar cell from grass clippings

Research paper: doi:10.1038/nature11652 – “Continuous gas-phase synthesis of nanowires with tunable properties”

http://www.extremetech.com/extreme/153037-a-cheap-nanowire-ink-that-can-boost-existing-solar-cell-efficiency-by-25