Solar Cells Able to Generate High Efficiency Power

Tiny, multilayer stacks of solar cells are able to generate ultrahigh efficiency power, researchers at the University of Illinois at Urbana-Champaign report. 

New technologies using a printing process allowed scientists to convert the Sun's light into electrical power, a process referred to as photovoltaics, a may soon make solar energy a viable option.

"A few simple ideas in materials science and device assembly allow us to bypass many of the limitations of traditional photovoltaic technologies," John Rogers, whose team came up with the concept, explained in a press release.

Industry experts not involved in the study predict that solar energy could potentially cost less than coal, natural gas, and nuclear energy production costs, the authors noted in Nature Materials.

The innovative printing approach allows the researchers to manipulate ultrathin, small semiconductor elements that can be stacked on top of one another to yield an unusual type of solar cell capable of operating across the entire solar spectrum at exceptionally high efficiency.

"Quadruple-junction, four-terminal solar cells that we can build in this way have individually measured efficiencies of 43.9 percent," Rogers said.

He also asserted that this method yields in total over 95 percent efficiency when the stacks of cells are combined.

By stacking the solar cells on top of one another, the top layer - consisting of a three-junction (3J) microcell with its own anti-reflective coating - captures light with wavelengths between 300 nm and 1,300 nm. Wavelengths from 1,300 nm to 1,700 nm pass through to the bottom cell with minimal light reflections, due to the thin layer of a unique type of chalcogenide glass.

The Sun has long been a dependable energy source, but Roger and his colleagues seem to have paved the way to better harnessing this power.

"This is very nice work. The results are impressive, and the schemes appear to provide a route to ultra-high efficiency photovoltaics, with strong potential for utility-scale power generation," stated Ali Javey, a professor of electrical engineering at the University of California, Berkeley, who was not involved in this study.