So what's so special about a blue LED?

Steve Woodward, Child studying by solar light, ABC.net.au

***

One of this year's Nobel prizes was awarded to the Japanese inventors of the blue light-emitting diode (LED). NobelPrize.org explains that

by using blue LEDs, white light can be created in a new way. With the advent of LED lamps we now have more long-lasting and more efficient alternatives to older light sources.

Popular Science asked the same question I did--"Why A Blue LED Is Worth A Nobel Prize"--and went on to say:

LEDs are basically semiconductors that have been built so they emit light when they're activated. Different chemicals give different LEDs their colors. Engineers made the first LEDs in the 1950s and 60s. Early iterations included laser-emitting devices that worked only when bathed in liquid nitrogen. At the time, scientists developed LEDs that emitted everything from infrared light to green light… but they couldn't quite get to blue. That required chemicals, including carefully-created crystals, that they weren't yet able to make in the lab.

Once they did figure it out, however, the results were remarkable. A modern white LED lightblub converts more than 50 percent of the electricity it uses into light. Compare that to the 4 percent conversion rate for incandescent bulbs, and you have one efficient bulb. Besides saving money and electricity for all users, white LEDs' efficiency makes them appealing for getting lighting to folks living in regions without electricity supply. A solar installation can charge an LED lamp to last a long time, allowing kids to do homework at night and small businesses to continue working after dark.

***

LEDs! 

PiccoloNamek on Wikimedia Commons, CC BY-SA 3.0

***

This NPR blog, Goats and Soda, calls LED lights a 'transformative technology' in the developing world, replacing kerosene with solar power. Lighting Global supports a burgeoning market for off-grid lighting.

Problem solved...mostly.

But what about the times and places when and where the sun doesn't shine so much? Researchers are working on it: "Artificial Photosynthesis: Saving Solar Energy for a Rainy Day." If you're interested in the topic of photovoltaics, you can sign up at The Optical Society (OSA) to get current and reliable information.

***

Artificial photosynthesis graphic, OSA

***

-- Marge

Traveling the electron transport chain

Because of new developments, photosynthesis has been in the news lately.  Science News reports "Artificial Forest for Solar Water-Splitting: First Fully Integrated Artificial Photosynthesis Nanosystem."  Quoting from the article --

While "artificial leaf" is the popular term for such a system, the key to this success was an "artificial forest."

"Similar to the chloroplasts in green plants that carry out photosynthesis, our artificial photosynthetic system is composed of two semiconductor light absorbers, an interfacial layer for charge transport, and spatially separated co-catalysts," says Peidong Yang, a chemist with Berkeley Lab's Materials Sciences Division, who led this research. "To facilitate solar water- splitting in our system, we synthesized tree-like nanowire heterostructures, consisting of silicon trunks and titanium oxide branches. Visually, arrays of these nanostructures very much resemble an artificial forest."

MIT News reports in "Secret of efficient photosynthesis is decoded" that "Purple bacteria are among Earth’s oldest organisms, and among its most efficient in turning sunlight into usable chemical energy."

Shown below is simple diagram of photosynthesis found Equinox Overseas Investments.

For current news on photosynthesis, try e! Science News' list, continually "updated by artificial intelligence."  At the top of the list (warning: link is flaky) is an article from Science Centric: "Unique close-up of the dynamics of photosynthesis."

Below is a more detailed explanation of the photosynthetic process (be prepared for alphabet soup and scientific jargon), posted to YouTube by ndsuvirtualcell.

For current research on artificial photosynthesis, keep an eye on JCAP (Joint Center for Artificial Photosynthesis), a research program dedicated to the development of an artificial solar-fuel generation technology.  Nanowires promise to transform solar panel technology, according to this article at R&D Magazine.  Note that "an array of nanowires may attain 33% efficiency."

Considering that "The Sun produces enough energy in one hour to power all human activity on Earth for a full year" (JCAP), artificial photosynthesis promises to be a rewarding venture.

-- Marge

What's happening in artificial photosynthesis

Enough of politics...how about a little science for today?

With the promise of gas prices rising again and a depletable supply of oil, the time to start developing alternate sources of energy is long past. One promising field is artificial photosynthesis.  The sun pumps out an amazing amount of energy, but solar panels can only capture about 30% of it, although they're getting better all the time.

While the main purpose of natural photosynthesis is to nourish the plant (and, in the larger scale of nature, cleanses the air), the purposes of artificial photosynthesis are different, more specific to whether the output is carbon or oxygen. These purposes include splitting water to produce hydrogen for fuel cells and carbon fixation for biofuels.

The article "How Artificial Photosynthesis Works" from How Stuff works by Julia Layton explains the process. There is now a Joint Center for Artificial Photosynthesis (JCAP), established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub. An article, dated April of 2012, at Science Daily reports "Artificial Photosynthesis Breakthrough: Fast Molecular Catalyzer."

Details of the photosynthesic process are amazingly complex, so I opted for a much-simplified diagram from Estrella Mountain Community College's page on photosynthesis.

***

***

I've long thought that artificial photosynthesis would lend itself to developing a battery.  Apparently so do two chemists at the University of Texas -- Christopher Bielawski and Jonathan Sessler. Their work is detailed in the article, dated September 2010, "Electron Switch Between Molecules Points Way to New High-Powered Organic Batteries."

Note: this post was updated in May, 2016. And there's a lot more information on this topic out there.

-- Marge