It’s 2015, I always thought the world look like the jetsons right now with flying cars and clean energy? While we’re still waiting on a flying car, clean energy, especially solar, has come a long away. Hey guys Julia here for DNews We’ve talked about solar power here on DNews before a lot. To see how solar power works check out this episode right here. But just a quick recap, solar panels are made of photovoltaic cells. These cells convert sunlight into energy by using photons from the sun to knock loose electrons. These cells are typically made up of a silicon wafer sandwich. One wafer is positively charged, the other negative, this creates an electric field. Phosphorus is added to top the layer to increase the amount of electrons there and boron makes the bottom more positive. Photons from the sun knock an electron out of that electrical field and then the cell has some other parts that use that electron as energy.
That’s the basics. Solar panels aren’t a new technology, they’ve been around for over a hundred years. The first “solar cell” was patented in 1888. But since then, it’s kind of been slow going. Almost 90 years later RCA Laboratories come out with the silicon version of a solar cell… but it only had an efficiency of 1.1% Basically that means for the amount of energy going into a solar cell from the sun, only 1.1% of that is converted into usable electricity. And research into solar technology is like I said, slow going. One researcher said gains of 0.2 percent are the norm and gains of 1 percent are seen as significant breakthroughs. Since the 70s efficiency has only increased from 1.1% to around 20% for most conventional models. In comparison traditional forms of electricity from fossil fuels are only at about 40% efficient. But even the US Government wants to do better.
Over a decade ago the DARPA initiative put out a request for 50% efficiency in solar panels. So far, research has come close. In 2007 researchers from the University of Delaware announced they created a cell with 42.8 percent efficiency up from 40%, which in this field was a huge deal. Their solar panel gained in efficiency by separating sunlight into three different energy bins of high, medium and low, and directs them onto cells of various light-sensitive materials to cover the solar spectrum. And in late 2014 Australian researchers announce a 40% efficient panel in the journal Progress in Photovoltaics. It boosted efficiency by including another filter to capture more bandwidths of light that are usually wasted by other models. But it’s still not the typical model you’d see on homes. Most conventional panels only reach an efficiency of about 20%. But maybe the future doesn’t even lie with silicon.
Research into a different material called perovskite has taken off over the past few years. Perovskite is a naturally occurring mineral with a crystalline structure made out of calcium and titanium. But it’s really easy to synthesize in a lab out of a organic-inorganic hybrid of lead or tin halide that's mixed with organic groups like methylammonium. The crystalline structure makes it especially good for solar applications. But one of the most exciting things about this new type of solar cell is how far it’s come in such a short time. Perovskite research seems to be moving at very brisk pace compared to silicon. In only six years it jumped from 3.8% efficiency in 2009 to a certified 20.1% in 2015, which is on par with conventional silicon panels. So maybe they could reach DARPA’s goal in no time. One materials scientist I spoke with, Daniel Dryden said “their insane rate of improvement is definitely worth paying attention to as more than just the newest fad.
”. While perovskite panels aren’t on the market yet, some start ups promise they’ll have some ready to go by 2017. So it’s definitely something to keep an eye on. One of the other great features of perovskite that gets researchers excited is how cheap it is to make. Which could benefit those in rural areas without access to traditional electricity. Be sure to check out our other episode on Seeker Stories, where we discovered how constant blackouts and a lack of electricity in general impacts daily life in Tanzania. To learn more about energy poverty, visit One.org/energy.