A flexible solar sheet that captures more available light than current solar panels could be available in the next five years. A team of researchers led by University of Missouri professor of chemical engineering, Patrick Pinhero, has developed what is essentially a thin, flexible sheet of small antennas called nantenna that can harvest heat from industrial processes and convert it into usable energy.
The initial concept of designing nantennas was based on scaling of radio frequency antenna theory to the infrared and visible regions. For Mr. Pinhero, using traditional photovoltaic methods of solar collection is inefficient and neglects much of the available solar electromagnetic spectrum.
The team intends to extend this concept to a nantenna capable of collecting solar irradiation in the near infrared and optical regions of the solar spectrum. Because it can absorb infrared radiation, the material has the capacity to capture more than 90 percent of available light compared to traditional photovoltaics which only use visible light or about 20 percent of the sun's rays that reach the earth.
"Our overall goal is to collect and utilize as much solar energy as theoretically possible and bring it to the commercial market in an inexpensive package that is accessible to everyone," said Mr. Pinhero. Mr. Pinhero was previously with the United States Department of Energy's Idaho National Laboratory and is working with his former team there along with Garrett Moddel, an electric engineering professor at the University of Colorado, and Dennis Salfer of MicroContinumm, Inc. of Cambridge, Massachusetts.
The original team developed nano-antenna in 2008 based on tiny gold squares or spirals set in a specially treated form of polyethylene, a material used in plastic bags. They had the ability to absorb infrared radiation that the team felt would make them promising for use in cooling devices as they can absorb infrared radiation given off as heat from objects such as buildings or computers. Mr. Pinhero and his team have now developed a way to extract electricity from this collected heat using special high-speed electrical circuitry.
The team has secured funding from the D.O.E. and private investors and the second phase would feature an energy-harvesting device using this material for existing industrial infrastructure. Within five years, the team believes that they will have a product that complements conventional solar panels. Because of the materials flexibility, it could have applications for building integrated photovoltaics such as solar roof shingles or even be custom-made to power vehicles.
Energy from sunlight comes in a broad spectrum of electromagnetic radiation. The most commonly known is the visible spectrum that can be seen by the human eye. Visible light is also the spectrum that traditional solar cells can absorb and convert into energy. Infrared light is also a part of the electromagnetic spectrum and is actually more abundant then visible light. One-third of solar energy that comes to the Earth is infrared, and majority of solar panels cannot use that wavelength.
Finding ways to harness this portion of the electromagnetic spectrum is of great interest to scientists seeking to improve the efficiency of solar power systems.
Source; Apec-vc
