In order for solar to become a financially viable alternative to fossil fuels, the efficiency must increase greatly. This mean breaking through the theoretical limit of 10% efficiency (the Shockley-Quiesser limit) and creating solar cells that offer cost-effective clean energy.
Scientists up to this point have struggled with truly understanding the materials that make up solar cells, lessening their ability to harness the technology and make it work the way it needs to. This may be changing with the help of Eric Bittner from the University of Houston and Carlos Silva of the University of Montreal.
What these two researchers have done differently was looking at solar cells from a quantum mechanical perspective. Bittner noted that “by understanding these effects and making use of the in the design of a solar cell, we believe you can improve efficiency.”
Silva added, Silva added, “In polymeric semiconductors, where plastics form the active layer of solar cells, the electronic structure of the material is intimately correlated with the vibrational motion within the polymer chain. Quantum-mechanical effects due to such vibrational-electron coupling give rise to a plethora of interesting physical processes that can be controlled to optimize solar cell efficiencies by designing materials that best exploit them.”
Bittner mentions that the benefit of their model is that it offers insight into what is happening within solar cell systems.
“Our theoretical model accomplishes things that you can’t get from a molecular model,” he said. “It is mostly a mathematical model that allows us to look at a much larger system with thousands of molecules. You can’t do ordinary quantum chemistry calculations on a system of that size.”
The next steps in this process include setting up experiments to probe the outcomes predicted by the model and then collaborating with scientists who are experts in making polymers and fabricating solar cells.