Published on January 30th, 2013 | by James Ayre7
Next-Generation Of Solar Cells, Capturing More Sunlight With Microbeads
“Micro beads” may be the key to extremely thin (and much cheaper) next generation solar cells. Solar cells 20 times thinner than the solar cells of today are only 5-7 years off, according to the nano-scientists that are currently developing them.
The estimate, as of right now, is that the super-thin solar cells will be on the market by 2020, which should help to greatly cut down on manufacturing and production costs.
“Over 90 per cent of the current electricity generated by solar panels is made by silicon plates that are 200 micrometres thick. Several billion of these are produced every year. The problem is the large consumption of silicon: five grams per watt.”
And even though silicon is one of the most abundant elements on the planet, the ‘pure silicon’ used in solar cells is very expensive and energy intensive to create. And a lot simply ends up discarded during the manufacturing process. There has been some recent research that should help to cut down on wasted silicon, though, so other improvements are also being made there.
“About 100,000 tonnes of silicon are consumed every year. However, there is obviously something fundamentally wrong when half of the silicon must be thrown away during the manufacturing process”, says Erik Marstein, the Head of the Norwegian Research Center for Solar Cell Technology, the Head of Research for the solar cell unit at the Institute for Energy Technology at Kjeller outside of Oslo, and an Associate Professor in the Department of Physics at the University of Oslo.
While solar cells have been becoming much cheaper in recent years, the researchers say that manufacturing practices must improve in order to allow solar companies to really make money. “It is difficult to make money producing solar cells at current prices. To make money, solar cells must be manufactured much more cheaply…. The most obvious way ahead is to make very thin solar cell slices, without increasing costs. This general rule applies to all types of solar cells: the more electrons sunlight pushes out, the more electricity. And the more energy in the electrons, the higher the voltage.”
“The thinner the solar cells become, the easier it is to extract the electricity. In principle, there will therefore be a higher voltage and more electricity in thinner cells. We are now developing solar cells that are at least as good as the current ones, but that can be made with just one twentieth of the silicon. This means that the consumption of silicon can be reduced by 95 per cent”, Erik Marstein.
There is a downside though, with thinner plates less sunlight is trapped. But the researchers have come up with a very effective way to address this, by forcing the light to move sideways.
“We can increase the apparent thickness 25 times by forcing the light up and down all the time. We have calculated what this back sheet (that redirects the light) must look like and are currently studying which structures work.”
Uglestad microbeads appear to be one of the best options. For those that don’t know, Uglestad microbeads are very small plastic spheres of a exactly uniform size that have a variety of different uses, and strange characteristics.
“We can force the Uglestad microbeads to lie close together on the silicon surface, in an almost perfect periodic pattern. Laboratory trials have shown that the microbeads can be used as a mask.” Lasers can then be used to etch indentations around the microbeads.
“We are now investigating whether this and other methods can be scaled up for industrial production. We have great faith in this, and are currently in discussions with multiple industrial partners, but we cannot yet say who.”
Improvements to manufacturing processes, such as this, and other cost-saving measures could do a lot to help solar power companies become more profitable, and to stay in business. The solar industry has been going through something of a “shakeout” recently — as some of the less competitive companies have been going out of business, technologies such as this will continue to drive strong competition and improvements to solar technology well into the future.
Source: University of Oslo
Image Credits: Yngve Vogt