A team of scientists from the University of Texas at Austin have discovered a way to double the efficiency of solar cells. The process consists in capturing more of the available energy in sunlight (including energy at the high end of the scale), using nanoscale crystals called quantum dots. Currently, the rate is about 31% for conventional solar cells, but due to this process the team hope to boost the solar efficiency up to a whopping 66%.
Until now, high energy sunlight had escaped in the form of heat, being too hot to be converted into electricity. The research team led by chemist Xiaoyang Zhu has found that by using quantum dots, the hot electrons are conducted out, having conductive properties that can be precisely controlled.
Due to the fact that conventional quantum dots are made of toxic heavy metals, researchers have used quantum dots made of lead selenide (a crystalline form of lead). According to Zhu, in this process could be used with other materials, opening up the potential to build a high efficiency solar cell with quantum dots made of non-toxic materials.
The use of quantum dots in solar cells and the high energy levels they could capture means that fossil fuels could become cost-competitive with solar cells at an increasingly rapid pace. Intermittent sources such as wind and solar can generate energy streams that are every bit as steady and reliable as natural gas, oil or coal.