Researchers from North Carolina State University have developed a new method for connecting stacked photovoltaic cells which promises to enhance the overall efficiency of concentrated solar power.
The stacking method involves placing several solar cells on top of each other, and is at present the most efficient form of social power installation on the market, capable of converting 45 per cent of the sun’s energy they harvest into power.
In order for this arrangement to work, designers must ensure that the connection junctions between individual cells do not absorb any solar energy or lead to voltage loss from the cells.
Researchers at North Carolina State University have developed a new method for altering the connecting junctions which they claim completely prevents voltage loss.
“We have discovered that by inserting a very thin film of gallium arsenide into the connection junction of stacked cells we can virtually eliminate voltage loss without blocking any of the solar energy,” said Dr. Salah Bedair, North Carolina State professor of electrical engineering.
The development promises to radically raise the conversion efficiency of solar installations by vastly increasing the amount of sunlight they can harvest without loss of voltage.
Solar power companies often use lenses to concentrate the sun’s energy, at levels of one sun (meaning no sunlight) to 4,000 suns. Past the 700 sun threshold, however, connection junctions begin to seep voltage, with the amount increasing in tandem with a rising number of suns.
The technology developed by Bedair and his team raises the voltage loss threshold to well beyond amount of suns that concentrating lenses are likely to produce.
“We have created a connection junction that loses almost no voltage, even when the stacked solar cell is exposed to 70,000 suns of solar energy,” Bedair said. “That is more than sufficient for practical purposes, since concentrating lenses are unlikely to create more than 4,000 or 5,000 suns of energy.”
“This should reduce overall costs for the energy industry because, rather than creating large, expensive solar cells, you can use much smaller cells that produce just as much electricity by absorbing intensified solar energy from concentrating lenses. And concentrating lenses are relatively inexpensive.”