University of Toronto
Enough radiation energy reaches the earth in one hour to supply the world’s total energy needs for over a year. However, current photovoltaic solar-energy systems typically convert only 15 percent of the energy in sunlight into electricity.
Part of the reason is that solar panel technology mainly captures one band on the spectrum of the sun's energy—visible light. Capturing more of the sun’s clean, abundant energy relies on harvesting energy from invisible bands, such as ultraviolet and infrared. Researchers have recently been making strides in using semiconductor quantum dots that can do just that—potentially reaching almost 50 percent efficiency.
Graham Carey’s research is exploring some of the key challenges in making quantum dot photovoltaic systems more efficient. Quantum dots—microscopic pieces of semiconductor—capture different kinds of light depending on the size of the dot, and can be layered onto a surface from a liquid, like paint. Carey’s research looks at ways of making the individual layers more stable. He is also strengthening the connections between layers to minimize current and voltage loss to create a more efficient system.
Carey, winner of the doctoral NSERC 2012 André Hamer Postgraduate Prize, works with the University of Toronto’s cross-disciplinary Sargent Group, which researches applications for discoveries in nanoscience.
Highly efficient quantum dot photovoltaic systems are cheap to produce and much lighter than current solar panels, providing a cost-effective alternative to systems currently on the market. In fact, such an energy innovation promises to be even cheaper than other forms of energy such as fossil fuels, which would deliver significant economic benefits for Canada and environmental benefits for humanity.