Quantum mechanics can be used to create organic solar cells that are more stable and easier to produce. These are the results of new research from the University of Gothenburg.
Organic solar cells have many advantages over traditional silicon-based solar cells. They can be made inexpensively on a large scale using printing presses and they are lightweight, malleable and flexible. The problem is, today’s organic solar cells are not as stable and efficient as silicon-based solar cells. In a new study, a research group has tackled this problem and found a way that can lead to more cost-effective solar cell technology.
“There are excellent opportunities to use quantum efficiencies to modify different chemical and material characteristics. In this study, we present a method that allows to increase energy diffusion in organic materials. This allows us to create organic solar cells with a simpler structure, ”says Karl Börjesson, professor of physical chemistry at Gothenburg University and lead author of the study.
Basically, it’s about making sure that the energy from the solar cells is actually transferred to the right place. Organic solar cells contain two materials and the energy absorbed by the sun must be diffused – to travel – at the interface between the materials. But diffusion is an inefficient process because energy moves slowly and may be lost as heat before reaching this interface. The solution was to mix the two materials in solar cells to reduce the distance and thus the energy reached the interface more quickly. Unfortunately, this also leads to the solar cells not being in thermodynamic equilibrium, making the design less durable over time than it could possibly be.
The researchers show that the new method allows energy to be transferred over a longer distance, which means that the complicated mixing of materials in solar cells can be avoided. The key behind the method is quantum effects, where light and material are combined in hybrid light-matter states.
“When we strongly couple light and matter, the energy is distributed throughout the system. If the system – as in this case – consists of several materials, the energy can be channeled to the interface. energy moves faster to interfaces when materials are strongly coupled. This means that the solar cell materials do not need to be physically mixed since they are mixed at the quantum level. This also leads to a system in thermodynamic equilibrium. “said Karl Börjesson.
According to Börjesson, the discovery may influence the way organic solar cells are made, as it becomes possible to increase their durability while solar cells can be made with a simple layered structure. He also notes that the research is actually the result of a concept already present in nature.
“Nature uses strong coupling between molecules to efficiently transfer solar energy in photosynthesis. In principle, we have shown that the same basic concept can be applied to organic solar cells.”
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Material provided by University of Gothenburg. Original written by Ulrika Ernström. Note: Content can be changed for style and length.