Solar Energy Has Failed Us, Here’s How to Fix It
Shedding Light on Quantum Dot Solutions in Solar Energy
In terms of energy, the sun is by far our best resource. Since grade school, we have been taught that the sun is the most efficient way to get energy. We are on the brink of an energy revolution, and for it to happen, solar needs to get better, and it needs to get better now. With the advent of quantum dot solar technology, solar energy will get cleaner, more integrated, and more efficient.
Solar Kinda Sucks…
Solar cells today have much room for improvement. Currently, the efficiency of solar cells is akin to filling a pool with a bucket with holes on the bottom. Sure it could get the job done, but there’s so much being lost.
The average commercial solar panel converts 17–20% of sunlight into electricity. The amount of energy captured fails to power individual homes, let alone cities. The lack of efficiency derives from the constraints of their materials. Most semiconductors can only capture up to 1/5 of solar light, leaving swaths of the solar spectrum unused.
Not only that, but the manufacturing of current solar cells is incredibly damaging to the environment, and the cells themselves pose a danger as well. Most commercial solar panels are made out of semiconductors like cadmium telluride (CdTe) and other heavy metals. These heavy metals cause great ecological damage and pose a great health risk when they pile up in landfills. As if that wasn’t enough, they also take up a ton of space, creating acres of unusable land.
…But It Can Get Better
Nanotechnology presents us with a better option for our solar panels. When I say nanotechnology, I’m talking about a scale of tens or hundreds of atoms. A quantum dot (QD) is a semiconductor nanoparticle that is one ten thousandth the width of a human hair. Companies such as Samsung are making TVs out of quantum dots, because when you introduce energy to a quantum dot, it releases light. This mechanic goes both ways; when you introduce light to a QD, it emits energy. This process can be controlled by adjusting the size of the particles, controlling its color or what wavelength of light it can capture.
The synthesis of QDs themselves is much cleaner compared to their contemporary. Processes like colloidal synthesis make things much cleaner. Colloidal synthesis can be explained through cooking; the process is much like following a baking recipe. You have to mix chemicals like zinc salts, solvents, and ligands (which act like binding agents for molecules). Sulfur or selenium sources like sulfur powder are then used to control the size of the quantum dots. Finally, you have to precisely heat them to stimulate nanocrystal growth, and now you have a quantum dot cake. No heavy metals, no water overuse, no harmful processes.
Well… How Exactly Do They Work?
When sunlight strikes a quantum dot solar cell, it excites the electrons in the quantum dots, making them jump from a lower energy level (valence band) to a higher one (conduction band). This creates a “hole” where the electron used to be, creating a positive charge in it’s absence. These pairs of moved electrons and the “holes” they left behind alone cannot do much, but when the pairs are separated by an internal electric field, like those created by junctions of materials like titanium dioxide (TiO2) or zinc oxide (ZnO), electricity is generated. Each part of the junction is either n-type or p-type, and this junction pushes electrons toward the n-type region and holes toward the p-type region, generating an electric field with the movement, and voila, energy.
Dizzy Yet?
A lot of information was just thrown at you, but essentially, the movement of internal electric fields generates electricity. Doing this process cleanly is a great improvement on current technologies, but that is not all quantum dot solar cells can offer.
If Life Gives You… Glass?
One of the biggest advantages of quantum dot solar cells (QDSCs) is that they are incredibly adaptable. QDSCs can transform a regular piece of glass into a solar panel, making it incredibly useful for using existing infrastructure instead of needing to clear out large swaths of land just for solar panels. This is done rather simply, with a simple mix of QDs and a binding agent. This not only expands the possibilities to windows, but it could also expand to screens and even wearable tech.
Next articles will be focused more on the biotech side of nanotechnology. Follow along to learn a little bit more, and feel free to reach out and start a conversation!
Thank you for reading, and stay tuned for my future articles!
Thank you to Zayna for being a wonderful reviewer and editor!
