Innovations in Solar Energy

Solar energy offers lots of promise for reducing our dependence on fossil fuels and cutting greenhouse gas emissions. In fact, some researchers say the sunlight hitting just 9 percent of the Mojave Desert in California could provide enough energy to power the entire U.S.

One of the hurdles still facing the technology, though, is the limited efficiency of today's solar cells. For all the sun energy that beams down onto Earth each day, solar cells still manage to convert only a small percentage into electricity. However, new discoveries and innovations are emerging regularly that could help us solve the solar cell efficiency problem.

Following are some of the most recent advances in solar cell efficiency:

Researchers at Northwestern University have found they can boost a solar cell's energy conversion rate by coating part of the cell with an ultrathin (5 to 10 nanometers thick) layer of nickel oxide. The process is not only inexpensive but can increase a solar cell's voltage by about 40 percent and improve the efficiency of energy conversion from the standard 3 to 4 percent to 5.2 to 5.6 percent.

Solar cell efficiency could be doubled by using silicon crystal coated with single-crystal layers of a semiconductor compound like gallium-arsenide, according to a discovery by two professors of engineering physics at McMaster University in Canada. The innovation has already generated a $4.1 million investment from the Ontario Centers of Excellence and ARISE Technologies Corp., a solar energy company.

A Swiss research team recently developed a solar cell that set a new record for energy conversion efficiency for a dye-sensitized cell. Dye-sensitized solar cells, which feature dye molecules on an electrode of titanium oxide, are typically inexpensive, easy to make and can have energy conversion efficiencies of more than 11 percent. However, the volatile compounds needed to make such cells mean they degrade quickly in outdoor conditions. The new Swiss innovation eliminates those volatile compounds, meaning it can remain stable and effective outdoors.