by: Klint Finley
August 1, 2012
Two things hold back the mass adoption of solar energy as a source of sustainable energy. One is the need to store and transmit excess power, a problem people like Danielle Fong are working on solving by developing innovative new ways to store power. The other is the high cost of solar panels. One of the reasons solar panels are so expensive is that it’s tricky to extract electric currents from semiconductors, the materials used to convert solar radiation into electrical energy.
Up til now, this could only be done with a few materials — usually silicon. But a new breakthrough will enable manufacturers to make efficient photovoltaics using almost any semiconductor, including cheap and abundant materials like metal oxides, sulfides, and phosphides.
A typical photovoltaic cell is built with silicon and treated with chemicals. This treatment is called “doping,” and it creates the driving force needed to extract power from the cell. Photovoltaics can also be built with cheaper materials but many of these can’t be doped chemically. But a method developed by Professor Alex Zettl’s research group at Lawrence Berkeley National Laboratory and University of California at Berkeley makes it possible to dope nearly any semiconductor by applying an electric field instead of chemicals. The method is described in a paper published in the journal Nano Letters.