So what's so special about a blue LED?

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

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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.

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LEDs! 

PiccoloNamek on Wikimedia Commons, CC BY-SA 3.0

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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.

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Artificial photosynthesis graphic, OSA

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-- Marge