Meet the Most Efficient Solar Cell in the World

May 18, 2016 by Kate Smith

Scientists from the University of New South Wales have developed the world’s most efficient solar cell.

A team of researchers hailing from the University of New South Wales has developed the world’s most efficient solar cell.

A team at Australia’s UNSW, led by Dr. Mark Keevers and Professor Martin Green, have developed a solar cell design capable of converting unfocused solar energy into electricity at a ground-breaking 34.5% efficiency.



Dr. Mark Keevers and the prototype. Image courtesy of UNSW.


What’s truly exceptional about this level of efficiency is that it’s being achieved when converting unfocused light. This means that the cell can attain 34.5% efficiency when converting light that’s naturally occurring. In the past, efficiency levels have been measured when taking only focused light into account, light that had been concentrated with the use of mirrors.

This cell is markedly more efficient, even when left to absorb light from a rooftop with no light concentration.

The key to the cells’ hyper-efficiency is the use of prisms. By using a prism, the module is capable of trapping light and bouncing it around. This allows more opportunity for light energy to be absorbed before it can escape by reflecting away. It splits the incoming light into four bands that are then caught by a four-junction solar cell system.

On one side of the prism is a silicon cell. On the other side is a triple-junction cell. The triple-junction cell has three layers: germanium, indium-gallium-phosphide, and indium-gallium-arsenide. Each of these targets a specific wavelength of sunlight, essentially catching as much energy as possible via a multi-tiered filtering system. Much of the energy that the triple-junction cell does not catch, i.e. infrared light, ends up caught by the silicon cell.


Illustration of the four-junction system. Image courtesy of UNSW.


In addition to its extraordinary efficiency, the new solar cell design is also remarkably compact. The module in its entirety easily fits in the palm of one hand.


Photograph by Christopher Pearce. Image courtesy of the Sydney Morning Herald.


UNSW’s work with the Australian Centre for Advanced Photovoltaics (of which Professor Green is director and Dr. Keever is a Senior Fellow) has been producing large strides in solar technology for over 40 years. In 1989, it was UNSW researchers that first achieved 20% conversion efficiency with a photovoltaic cell.

In 2014, Keevers and his team at UNSW made news for breaking the world record for the highest solar energy conversion rate achieved for concentrated light— 40%. They accomplished this high efficiency by using commercially-available solar cells with a custom-made optical bandpass filter. The filter was able to capture and convert concentrated solar energy that was unavailable to the solar cells on their own, thus boosting overall efficiency to unprecedented levels.

The next step, according to Keevers, is to scale up the module so that it can be used outside of academia. Additionally, he says that the four-junction system could theoretically yield as much as 53% efficiency in the future.

Down the line, the team will aim to design a version of the module that’s capable of being manufactured for everyday use. Unfortunately, the new cell prototype is currently too expensive for mass commercial production. It could be several years before the modules become cheap enough to put on our roofs.

  • L
    LEhenson May 20, 2016

    So what - Solar is mostly a FRAUD.  Most pointing South, wasting more than 50% of potential energy - besides the DC to AC converters FAIL = ZERO power into the “grid” = FRAUD.  Where are the “tree huggers” when you want them?

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    • M
      mbelectronicdesign May 27, 2016
      What a dopey, fact-free comment. If you live in the USA, the sun is ALWAYS going to be in a southerly direction. Any system can fail but that doesn't make it fraud, fraud is stuff lik ethe Mickey Mouse things they sell to go on the end of antennae with the claim that they improve reception. I listen to satellite radio, the solar cells on those satellites are hardly fraud given they are running a 1,500 Watt system for up to 7 years. What a TROLL
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      • D
        dennisk May 27, 2016
        The facts are they all point south at a 22 degree angle for optimal! They normally last a life time of 15 to 20 years and have to be replaced. The same with wind generators. All the components last approximately the same length of time as you cant get a warranty to last longer than that! The power industry is getting more and more states to disallow feeding the power back into the power grid! So all this points to the DNC contracting with the Chinese who build all the parts and using nafta to avoid taxes and shoved it all down our throats like ACA and the new black is orange and ll the other BS the DNC has breen shoving down our throats for the last 75 years being the main power owning both houses of congress all that time!!! That last part flies way over democrats heads as they hate facts!
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