Utah, USA — Everybody loves a new world record, even more so when that record hints at the possibility of enormous strides in solar power energy generation. According to information coming out of the Centre for Solar Energy and Hydrogen Research (ZSW) in Baden-Württemberg, Germany, scientists there have once again snatched up the title as creators of the highest performing thin-film PV cell in the world.
Smashing the previous record of 21 percent efficiency set by Swedish solar manufacturer Midsummer, ZSW says it has achieved 21.7 percent cell efficiency in laboratory conditions by way of a solar cell made of copper indium gallium selenide (or CIGS, for short). The new breakthrough kicks up the outperformance of CIGS against multicrystalline solar cells by 1.3 percent and sets the stage for further improvements that could drive the cost of CIGS technology down to competitive levels.
Solar cell efficiency ratings indicate the percentage of incident sunlight that can be converted into electrical power. According to ZSW, CIGS modules currently available on the market are rated at an efficiency of roughly 15 percent. This is due to their larger size, which results in a lower overall efficiency.
The physical size of the CIGS solar cells developed by ZSW are small, but their potential is big. Each cell has an area of 0.5 square centimeters, which is the standard size for laboratory testing. Over 40 cells of identical size and makeup were manufactured, all of them achieving efficiency rates greater than 21 percent.
Professor Michael Powalla, head of the photovoltaics division of ZSW, said he is optimistic about even further technological improvements that will unlock additional CIGS solar cell potential.
“An efficiency rate of 23 percent is possible with a single junction,” Powalla said. “Reaching 23 to 25 percent is ambitious, but not impossible.” He added that efficiency rates above 25 percent will require “new components in the cell, like efficient tandem partners.”
According to Powalla, it may be another one to two years before ZSW’s superior performing thin-film solar cells can be put into mass production for widespread commercial availability. “The real challenge at the moment is to find investors.”
Funding for the research was provided by the Germany Federal Ministries for the Environment and for Economic Affairs and Energy. Additional monies were provided by the state of Baden-Württemberg. According to Powalla, that financial backing was essential to the results achieved.
“Without state R&D funding, this success would not have been possible,” Powalla said. “The risk in the development for private money would have been too high.” Powalla added that additional research funds are “absolutely needed” for continued research.
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