Solar Nanopaint Applications Boost Green Energy

Solar cells have been in the mainstream news for quite a while, almost since the initial discovery of the photovoltaic effect by French physicist A. E. Becquerel in 1839 and the subsequent explanation of the photoelectric law for which Albert Einstein received The Nobel Prize in Physics 1921.  With the emerging field of nanocrystal science and the varying quantum dot applications, solar cells may be undergoing a much needed technological advancement that could take the green solar energy industry in a different direction and help improve the overall energy yield of solar cell technology.  As single p-n junction type crystalline silicon devices begin to reach their maximum theoretical efficiency limits, quantum dots solar cells are taking a place among other research avenues, such as multiple layer approaches, with a goal of reducing the overall cost per watt and providing competition to the current electricity grid structure.

Fluorescent Quantum Dots Brightening Up Nanopaints
Credit: by argonne on Flickr

From Crystals To Quantum Dot Solar Panels

The discovery of quantum dots was made in the 1980's by Alexei Ekimov but it is unlikely that the Russian solid state physicist foresaw their full potential when he first encountered the semiconductor nanocrystals while working at Valvilov State Optical Institute in St. Petersburg, Russia.  However, these nanometere-scale particles have the potential to do great things.  These quantum dot particles have varying electron energy levels based on their exact size and these levels define a bandgap for the crystals.  Since the dots can be synthesized to suitable levels then it follows that their bandgaps can be fine tuned in order to better capture the varying spectrum of the sunlight in more efficient manners than Gallium Arsenide (GaAs) or traditional silicon cells.  In particular, vast improvement can be seen in the reception of infrared where lead sulfide PbS colloidal quantum dots are capable of receiving in the far infrared spectrum.  With around half of the total solar energy arriving on Earth being in the infrared spectrum this is a good improvement.

But perhaps, the most impressive thing about quantum dot solar cells is that they can be included in a solar nanopaint solution that can be applied to any conductive surface with the use of commonplace materials in order to create ad hoc solar cells.   If the quantum dot coatings can be manufactured at a cheap enough price then applications could be cost-effective enough for just about anyone to perform a diy solar cell conversion. Imagine using nanopaint on an entire statue in a park or something similar and being able to string together power sources from commonplace objects.  Researchers across the country are working to make this a reality but the primary problem facing current projects is that the energy efficiency of such nanocoatings is sub-par when compared to the light-to-energy conversion efficiency factors of the popular commercial silicon cells.  For example, researchers at NDnano (the University of Notre Dame's Center For Nano Science and Technology) have released findings of a nanopaint capable of about a 1% conversion factor.  There remains improvements to be done before one will be able to buy quantum dot solar cell nanopaint spray aerosols and gallons from Dupont, Benjamin Moore or Sherwin-Williams, but the day seems closer that more light photons will be harnessed for the green energy cause removing a portion of civilization's reliance on fossil fuels.

It will be interesting to see which companies are able to bring such quantum dot solar cell coatings to market.  NanoSonic, Inc, is one such company that is doing interesting things in the realm of nanoparticle science.  They already have a nanoparticle HybridShield Solar Coating which can be applied to existing photovoltaic cells or concentrating solar power (CSP) mirrors to improve efficiency ratings.    Their product lineup also includes interesting things like "Metal Rubber" and hydrophobic optical coatings.  It would not be hard to imagine the Virginia company adding such quantum dot brush-on or spray-on technology to their lineup.  Other companies such as those already producing dye-sensitized solar cells will probably find quantum dots a logical progression in their product introductions.  These dye-sensitized solar cell manufacturers include Dyesol (in collaboration with Sony), Solaronix, Hydrogen Solar, SolarPrint and more.  Sustainable energy in a spray gun.  Quantum Dots could even take graffitti bombing to the next level.  Can you imagine a graffitti crew bombing a freight train or other metallic surface with quantum nanopaint that runs something (perhaps led throwies) using the converted energy.  Breakthrough.