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| New Simplified Solar Cells With 330nm Thin Film Of Perovskite |
The new research by Professor Henry Snaith and colleagues from the University of Oxford, uses low-cost perovskite semiconductors in a simplified solar cell, to achieve sunlight to electricity conversion efficiencies similar to more expensive silicon solar cells.
Perovskite, or calcium titanium oxide, is seen as an inexpensive alternative to current silicon.
Writing in the journal Nature, Snaith and colleagues say their design is less complex to produce, making it a more suitable for large scale manufacturing.
The researchers claim that their perovskite solar cells "have a solar-to-electrical power conversion efficiency of over 15 per cent with an open-circuit voltage of 1.07 volts".
This comes close to the 17 to 23 per cent achieved by conventional silicon wafer solar cells, but which typically only produces about 0.7 volts.
Keeping it simple
Snaith and colleagues simplified design, sandwiches the perovskite semiconductor between the cell's electrodes allowing it to transport both positive and negative charges.
"The outstanding feature of the new cells is the high radiative efficiency for such a simply prepared material," says Professor Martin Green of the Australian Centre for Advanced Photovoltaics at the University of New South Wales (UNSW), who was not involved in the research.
Green says there are still questions about the stability of the new cells, and he's concerned about the levels of lead used in its production.
"They do involve lead in quantities that would considerably exceed requirements for compliance with legislation such as the European Restriction on Hazardous Substances directive, although photovoltaics are presently excluded from these requirements," says Green.
Perovskite technology is an area of growing interest for photovoltaics research, however Green thinks it will be difficult to displace the incumbent silicon technology, given recent cost reductions and silicon's higher energy conversion efficiency.
In 2009, the Green and colleagues at UNSW reported 25 per cent efficiency for a silicon-based solar cell. He suggests a combination of silicon and perovskite could result in further gains in efficiency.
"Perhaps the future lies in the complementary role identified in the paper as a high-band gap, high-voltage output cell stacked on top of a silicon cell to form a higher efficiency tandem cell," says Green.
"This is an approach our group is investigating since an energy conversion efficiency of 30 per cent may be possible."
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