energy to power our planet for a year." Solar power, however, has yet to deliver on this

promise from my children's television. Why is it so hard????

The sun shines on us every day, it comes down here we gather it up and we use it for energy

-- boom boom boom, done! But it's slightly more complicated than that, as you know.

In 1873, electrical engineer Willoughby Smith discovered the element selenium was photoconductive

-- when exposed to sunlight the metallic form of selenium becomes a semiconductor! Three

years later, other scientists discovered selenium could be used to create electricity from sunlight

-- dubbed the photoelectric effect. When sunlight hits a metal like selenium the electromagnetic

radiation is absorbed into it -- this fueled a whole HOST of physics nerds who are still

arguing whether light is a particle or a wave to this day! It was such a big deal the 1921

Nobel Prize in physics was awarded to Albert Einstein for explaining the photoelectric

effect, and for his contributions to theoretical physics… or whatever.

Eventually, scientists discovered that the light energy causes the freeing of electrons

which, if captured, could be used to generate electricity!. This photoelectric effect has

since been cultivated and researched and cultivated again, and the discovery that many different

elements display a photoelectric effect opened it up for use in a number of inventions! Photosensitive

cells are used in televisions, industrial processes, telecommunications, fiber optics,

copy machines, spectroscopy and telescope, and to sense pollution or emphasize other

lights like in night vision or infrared cameras; plus, of course, solar panels via a photovoltaic

cell. Photovoltaics were invented in the 1950s, and were popularized by the space program

as a way to power satellites. In the 1970s, pushes were made to modernize photovoltaics

for use in commercial and residential power -- but consumers mainly used them for calculators,

watches, radios and the like. Like a battery, a photovoltaic cell has a positive and negative

to guide the electrons into the system. Each cell uses a pair of silicon wafers -- one

doped with phosphorous (negative) and one with boron (positive).

From 1995 to 2010 solar energy use grew 20 percent a year -- and now, new inventions

are making it even more affordable. Firstly, in 2009, China created way more solar panels

than the market needed, and the price collapsed. And secondly, state and federal governments

in the United States, Germany, the United Kingdom and Japan are all giving subsidies

to cultivate better renewable energy systems. This means more supply and demand for this

technology, and as money flows through renewables, they get better!

Recently the University of Queen Mary in London revealed they can turn shrimp shells into

cheap solar panels. The shells of crustaceans contain chitin and chitosan which can be extracted

into CQD or carbon quantum dots -- CQD solar cells aren't new, but usually use expensive

ruthenium for its photoelectric properties. Instead, the researchers found this biomass

byproduct of the shrimp industry can be used to extract CQDs and create fully renewable,

cheap solar cells!

Pretty cool, huh? Fortunately solar cells aren't the only place finding greener solutions

for energy use -- Toyota is, too! The new Toyota Mirai is looking to the future with

sustainability in mind; fueled by hydrogen and leaving zero emissions behind.

Every year renewable energy is getting better, but it's not yet as efficient as we'd hope.

For more on the efficiency of the most common types of energy production, check out my video

about that here

What do YOU think is the most promising type of energy? Solar? Wind? Nuclear? Or plain

old coal, oil and gas? Why? Tell me your thoughts in the comments, and thanks for watching.

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