Recent improvement in solar panel technology and solar cell efficiency have made solar power one of the most promising renewable energy sources of the future.
Prices are continuously dropping, technological advances are continuously emerging, and science is continuously discovering new ways to bring innovation in this developing field. A team of researchers from North Dakota State University and University of South Dakota took on the task to find out which of the two most widely studied nanomaterials, quantum dots or nanowires, will enhance light absorption of future solar panels.
As new technologies in the field of solar power emerge almost every day, it is wise to sometimes take a step back and assess what is already there and how best to make use of it. This is what Andrei Kryjevski and his colleagues, Dimitri Kilin and Svetlana Kilina, did. In their study published in the Journal Renewable and Sustainable Energy, the scientists evaluated the optical and electronic properties of quantum dots and nanowires. Using a chemistry model called Density Functional Theory, the team was able to compute and compare the ability of the two nanomaterials to absorb light and how effective they are.
This method allowed the team to simulate the behavior of quantum dots, quantum dot chains and nanowires, without having to place them in the field. The scientists were able to establish that highest absorption is achieved with silicon quantum dot chains, as the individual nanospheres interact with each other. This, however, was strongly dependent on the way the structure is aligned in respect to the incoming light, and it is also applicable to nanowires. Last but not least, the scientists discovered that at lower energy, amorphous nanoparticles absorb much more light than crystalline-based nanomaterials, due to their atomic structure disorder.
The team concluded that an array or a nanowire made of amorphous quantum dots, gives the highest efficiency and allows much better transport of charge within the photovoltaic system. The team is now determined to simulate more realistic scenarios of the processes that occur in solar cells and use larger quantum dots, covered with organic ligands.