Thanks to researchers at EPFL`s Institute of Microengineering in Neuchatel, Switzerland, a new world record efficiency of 21.4% has been set for solar cells. This feat was done with HIT solar cells (heterojunction with intrinsic thin layer), and is by far the highest conversion efficiency ever achieved with the substrates that were used.
|Image credit: EPFL PV-lab|
These types of solar cells basically combine the best of monocrystalline and amorphous silicon. The team has applied a tiny film of amorphous silicon, not more than one hundredth of a micron thick, onto traditional monocrystalline wafers. This increases the effectiveness of the sensors, which ultimately boosts electrical output.
The research was recently presented by professor Cristoph Ballif, director of the Photovoltaics Laboratory (PV-lab), at the European Photovoltaic Solar Energy Conference and Exhibition in Frankfurt, Germany.
The theory behind solar cells based on heterojunction technology has been around for quite some time now. The main work of the Swiss research team has been to optimize the interface between the different silicon types.
They have come up with a process that uses p-doped silicon, which is the most common and cheapest type of crystalline silicon. By adding an ultrathin layer of amorphous silicon, the conversion efficiency of monocrystalline silicon has been pushed from 18-19% alone, to 21.4% with the hybrid solar cell.
The process has been validated Fraunhofer Institute for Solar Energy Systems (ISE) in Germany. The research paper is set to be published by the IEEE Journal of Photovoltaics.
Although the technology is still years away from being ready for the market, the innovation marks an important leap forward in the solar industry. Meyer Burger, one of the companies involved in the development of the process, has begun the work of commercialization machines that are capable of assemble the heterojunction sensors.
“Within three to five years, we expect to reach a production cost of $100 per square meter of sensors” estimates Stefaan De Wolf, one of the researchers at PV-lab. I`m curious to see if this innovation is just as exciting a couple of years down the line, and if it will actually help bring the cost of solar panels down.