A new technology that could enable low cost, high efficiency solar cells to be made from virtually any semiconductor material has been developed by researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory and the University of California Berkeley.
The technology, they believe, opens the door to the use of plentiful, relatively inexpensive semiconductors such as metal oxides, sulfides and phosphides, which have previously been considered unsuitable for solar cells because of the difficulty in chemically tailoring their properties.
“Solar technologies today face a cost to efficiency trade off that has slowed widespread implementation,” said physicist Alex Zettl, who led the research. “Our technology reduces the cost and complexity of fabricating solar cells and thereby provides what could be an important cost effective and environmentally friendly alternative that would accelerate the usage of solar energy.”
The researchers have dubbed the technology ‘screening-engineered field-effect photovoltaics’, or SFPV, because it utilises the electric field effect, a phenomenon by which the concentration of charge carriers in a semiconductor is altered by the application of an electric field.
With the SFPV technology, a carefully designed partially screening top electrode lets the gate electric field penetrate the electrode and more uniformly modulate the semiconductor carrier concentration and type to induce a p-n junction. This enables the creation of high quality p-n junctions in semiconductors that are extremely difficult to dope by conventional chemical methods.