Dec 25, 2011Science and Technology
Sun-believable: the new solar power generating paint

It is understandable why most people believe solar power is more of a futuristic technology than a modern one. Solar power is still prohibitively expensive (especially for the individual homeowner) and unreliable.


Unfortunately, the sun will always be a little bit flaky; and honestly, I am not sure it will even be here in the next 7 billion years. It will probably find a younger planet to warm. Luckily, most scientists have concentrated their energy on making solar power more affordable than making the sun reliable.


For example, researchers at the University of Notre Dame have recently published an article in the journal of “ACS Nano” on December 6, 2011 that details how the researchers developed a new paint on solar cell, which they mischievously named “Sun-believable.”


The researchers developed the paint by mixing semi-conductive nanoparticles, called quantum dots, with a water-alcohol based solution. These quantum dots consist of titanium dioxide coated with cadmium sulfide or cadmium selenide. Titanium dioxide (TiO2) is a naturally occurring and plentiful compound that is currently used in everything from sunscreen to food coloring. Cadmium sulfide and cadmium selenide are also commercially avaliable mass-produced materials used as a paint pigment and in other nano-applications [A Transformative One-Step Approach for Designing Nanocrystalline Solar Cells]


Since the compounds used to produce the nanoparticles are already widely used in other commercial, mass-produced products, Sun-believable paint should not cost much more than regular paint.


So is paint on solar cells the wave of the future?


The paint does have one major advantage: it is cheap. An overly expensive gallon of paint might cost 100 dollars. Typically, a gallon of paint can cover around 400 square feet. Therefore, for only 100 dollars, an individual could paint 400 square feet of solar cells onto their roof. Silicon based solar cells could cost around 40,000 dollars to cover a similar area.


Yet, Sun-believable does have some major flaws. For instance, the paint is only running at 1 percent efficiency. Typical silicon based solar cells that are currently available run at around 10 to 15 percent efficiency, which usually translates into around 10 watts per square foot [2 Solar & Wind Energy Calculations: The (very) Basics]

The Sun-believable paint would only get a single watt per square foot.


This means that while Sun-believable is 400 times cheaper than typical silicon based solar cells, Sun-believable is around 10 times less efficient.


Theoretically, this makes Sun-believable a better product, since it would only cost you 1000 dollars to expand the area of your solar cells by a factor of 10 and produce the same amount of electricity as the traditional silicon based solar cells. Realistically, most homeowners do not have a 4000 square feet of roof.


Another major flaw is that the paint has to be painted onto a translucent conductive material. This limits the products use. We shall not be turning our houses into giant electricity producing machines without first covering our house in the conductive material, and it limits my dream of painting the world in this solar cell paint to meet all energy needs. Moreover, the researchers failed to mention the cost of the conductive material, though it is reasonable to assume that it is, also, cheap.


Another potential problem with Sun-believable is how long the paint will last. Silicon based solar cells have a lifespan of around 20 to 25 years, and the most recent research has suggested that the solar cells might last much, much longer. Currently, the researchers do not know how stable the paint is. This is something the researchers are hoping to address in future research.


Overall, Sun-believable is a fantastic product, and it should interest anyone who has been paying attention to the world of solar energy advances. No, it is not the most revolutionary green tech advancement, nor is it the most spectacular, but it does appear to be the cheapest. And in the real world, cheapness often beats efficiency.

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