Solar energy conversion offers a solution to help mitigate global warming

March 6, 2007
Solar energy conversion offers a solution to help mitigate global warming
The dotted white line shows a nanodot inclusion in the crystalline structure of the thermoelectric material Ag0.86Pb18SbTe20, seen in high resolution transmission electron microscopy. Controlling nanoscale inclusions like this one will enable the next-generation of thermoelectric materials with significantly higher efficiency for converting the sun’s heat to electricity. The inclusion is about 10 nm in diameter. From Eric Quarez, Kuei-Fang Hsu, Robert Pcionek, N. Frangis, E. K. Polychroniadis, and Mercouri G. Kanatzidis, JACS 127, 9177 (2005). Image courtesy of M. Kanatzidis.

Solar energy has the power to reduce greenhouse gases and provide increased energy efficiency, says a scientist at the U.S. Department of Energy's Argonne National Laboratory, in a report published in the March issue of Physics Today.

Last month, The Intergovernmental Panel on Climate Change (IPCC) of the United Nations released a report confirming global warming is upon us and attributing the growing threat to the man-made burning of fossil fuels.

Opportunities to increase solar energy conversion as an alternative to fossil fuels are addressed in the Physics Today article, co-authored by George Crabtree, senior scientist and director of Argonne's Materials Science Division, and Nathan Lewis, professor of Chemistry at Caltech and director of its Molecular Materials Research Center.

Currently, between 80 percent and 85 percent of our energy comes from fossil fuels. However, fossil fuel resources are of finite extent and are distributed unevenly beneath Earth's surface. When fossil fuel is turned into useful energy through combustion, it often produces environmental pollutants that are harmful to human health and greenhouse gases that threaten the global climate. In contrast, solar resources are widely available and have a benign effect on the environment and climate, making it an appealing alternative energy source.

"Sunlight is not only the most plentiful energy resource on earth, it is also one of the most versatile, converting readily to electricity, fuel and heat," said Crabtree. "The challenge is to raise its conversion efficiency by factors of five or ten. That requires understanding the fundamental conversion phenomena at the nanoscale. We are just scratching the surface of this rich research field."

Argonne carries out forefront basic research on all three solar conversion routes. The laboratory is creating next-generation nanostructured solar cells using sophisticated atomic layer deposition techniques that replace expensive silicon with inexpensive titanium dioxide and chemical dyes. Its artificial photosynthesis program imitates nature using simple chemical components to convert sunlight, water and carbon dioxide directly into fuels like hydrogen, methane and ethanol. Its program on thermoelectric materials takes heat from the sun and converts it directly to electricity.

The Physics Today article is based on the conclusions contained in the report of the Basic Energy Sciences Workshop on Solar Energy Utilization sponsored by the U.S. Department of Energy. Crabtree and Lewis served as co-chairs of the workshop and principal editors of the report. The key conclusions of the report identified opportunities for higher solar energy efficiencies in the areas of:

-- Electricity – important research developments lie in the development of new, less expensive materials for solar cells, including organics, thin films, dyes and shuttle ions, and in understanding the dynamics of charge transfer across nanostructured interfaces.

-- Fuel – solar photons can be converted into chemical fuel more resourcefully by breeding or genetically engineering designer plants, connecting natural photosynthetic pathways in novel configurations and using artificial bio-inspired nanoscale systems.

-- Heat – controlling the size, density and distribution of nanodot inclusions during bulk synthesis could enhance thermoelectric performance and achieve more reliable and inexpensive electricity production from the sun's heat.

Source: Argonne National Laboratory

Explore further: Scientist at work: Searching for tiny neutrinos in the South Pole's thick ice

Related Stories

India sees clean cooking as climate action that saves lives

November 11, 2015

Kamlesh feeds the flames of a crude clay cookstove with kindling, kerosene and sunbaked discs of cow dung. She breathes in the billowing smoke, as she does for hours every day. Her eyes water and sting. Her throat feels scratchy ...

Climate vulnerable nations appeal for harder UN goal

November 11, 2015

A coalition of nations most at risk from climate change appealed Wednesday for a crucial UN summit to enshrine a much tougher target on global warming, warning that more than one billion lives were at stake.

China's gray smog has a blue lining: Air improves this year

November 12, 2015

Lawyer Wu Congsi has asthma and keeps air purifiers whirring away in his office, home and car to counter Beijing's hazardous smog. He prefers to stay inside unless the sky is blue. But this year, he's been able to regularly ...

Recommended for you

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.