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.

  • 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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    • 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
      Like. Reply
      • 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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    • Electrojim May 27, 2016
      Aha! Good observation, with respect to the cells 'pointing' in the wrong direction. I have an idea: Let's make the cells CYLINDRICAL so that they catch light from all directions. I'll bet we could even get federal funding for such a project. We could come up with a catchy name for a company that would manufacture these cells, merging the word 'solar' with 'cylindrical.' What do you think?
      Like. Reply
      • dennisk May 27, 2016
        What a babbling brook!!! He said south! You just wanted to get your cylindrical solar cell in there thinking that was a good idea! Half of that solar cell would receive no sun at all dividing the power output in half! Think before you jump in without any facts at all!!
        Like. Reply
    • IceBerg99 May 27, 2016
      Properly designed DC to AC inverters can last many years and can have efficiencies of 80% to 95+%, the intensity of sunlight at the earth's surface on a sunny day is roughly 1000 Watts per square meter. Even if the solar cells in the article end up achieving only half their stated efficiency, and even if your inverter is only 80% efficient, and even if you average the solar input over the entire 24-hour daily cycle, you still have an zero-carbon dioxide emission (not counting any emitted during the manufacture of the cells), zero-nuclear-waste, zero noise pollution and zero bird-kills power source. Other power sources fail too -- do you consider those "fraudulent"?
      Like. Reply
      • marksimmons May 27, 2016
        I think that it's worth mentioning also that the primary reason for the need for AC is due to the economy and practical requirement for the transmission and distribution of power over the "grid". We could (and have shown in the past) that with the ability to produce and make use of electricity in more localized and point of use applications, DC is a very efficient form of power. If it weren't for the obstacle (granted, this is a large one) of storage of the power, there are a lot of advantages to using relatively low voltage DC to power - much of what is needed for small municipalities and certainly for use by the average home. There vulnerabilities in the current implementation of the grid in the U.S. and many other countries, that could lead to huge economic losses if they are hacked into, or just collapse due to failure by natural causes. This is not a new concept by any means, but it bears consideration. Cheers to the researchers in this new efficiency in photovoltaics!
        Like. Reply
      • dennisk May 27, 2016
        It was diuscoivered over a hundred years ago that AC travels ofer the grid myuch mor efficiently than DC!! For DC power plants it would require a power plant in every so many miles instead of half the USA with AC!
        Like. Reply
  • krich May 27, 2016

    I have personally worked with CPV cells and liked what I saw. To the solar energy doubters out there, just because a technology doesn’t have an immediate and obvious use in the consumer market doesn’t mean it’s garbage. Solar is used extensively in transportation, communication, military, and space industries.  So go back to watching your reality shows, brought to you by satellites powered by solar energy.

    Like. Reply
    • dennisk May 27, 2016
      The problem isn't the cells as they are what they are. The problem is the federal government shoving them down our throats with a 15% efficiency buying all the parts from communist china and assembled in the USA! that goes for the wind generators also! Neodymium magnets cant be manufactured in the USA but they can be in grossly over populated communist countries! The USA doesn't manufacture but 1% of consumer items and the rest is shipped in from foreign countries!
      Like. Reply
  • mjkuwp94 May 29, 2016

    user Dennisk says
    “It was diuscoivered over a hundred years ago that AC travels ofer the grid myuch mor efficiently than DC!!  For DC power plants it would require a power plant in every so many miles instead of half the USA with AC!”

    which is sort of a factoid (not a fact).  I had long questioned why AC would have some kind of magic that DC doesn’t for flowing through a conductor.  I finally looked it up.  The AC vs DC was temporarily settled long ago using the constraints of technology at the time.

    An advantage AC had was that it was easy to change from high to low voltage with transformers.

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