ExtremeTech reports researchers from the University of California and Berkeley Lab have discovered a way of making photovoltaic cells out of any semiconducting material, potentially paving the way for much cheaper solar power.
Instead of having to use expensive silicon, the breakthrough may enable manufacturers to make solar cells from cheaper materials such as copper oxide.
Almost every solar panel on the market is made by cutting off two thin (200 micron, 0.2mm) slices from a large crystal of silicon, and then doping them with impurities to enhance the photovoltaic effect — phosphorous to make n-type silicon, and boron to make p-type silicon. These slices are layered together, electrodes are added to the top and bottom, the whole thing is framed in protective glass — and voila, a standard photovoltaic cell.
Now, in theory, you can dope any semiconductor — but cheaper, more-readily-available semiconductors, such as copper oxide, don’t retain dopants very well, eventually leading to the breakdown of the p-n junctions. Silicon holds dopants very well, but it isn’t cheap.
To get around this problem, the Californian researchers have developed a new type of solar cell called screening-engineered field-effect photovoltaics, or SFPV for short. Instead of physical doping, SFPVs use a minute electric field to achieve the same doping effect. While this electric field is present, the p-n junction remains and the photovoltaic cell continues to produce a lot of electricity. The energy required to produce this electric field is apparently a lot less than the energy produced by the photovoltaic effect.