Finding materials to lower the costs of solar panels, while maintaining their efficiency, is one of the tasks in which the international scientific community is working the most. In this long-distance race, a research team has just designed plastic-based solar cells that are easy to print and maintain an efficiency of 9.12%.
The percentage is a milestone in an area that many are working on: the creation of plastic solar systems based on the combination of conductive organic polymers. Progress in this area is important because it would lead to lighter and much cheaper solar cells. However, researchers face several challenges in advancing the exploitation of plastic for solar technology. The fundamental principle, that in these designs, efficiency is absolutely conditioned by the way in which the different materials that make up the cells are mixed, and by the way they crystallize in thin layers.
“Conventional organic solar cells have already achieved a good level of efficiency, but the polymer layers in such equipment generally require special treatment to ensure proper crystallization ”. This is explained by Yutaka Ie, leader of the team who found an alternative that facilitates the production of these cells, overcoming extremely complex and delicate processes.
In this work developed hand in hand by the Osaka University and German Institute for Polymer Research Max Planck, scientists have focused their efforts on reshaping cells from the combination of amorphous polymers. Thus, from a polymer previously prepared by the same team, he focused on adding a component to the structure of cells that would improve the conductivity of their holes. With this, as they later confirmed, it would be possible to increase the conversion efficiency of solar energy.
To understand the above mechanism, from Osaka University clarify how organic solar cells work. So, with them, everything is based on the activation of electrons in the polymer, something which is produced by the energy of light. Once this happens, the electrons are transferred to a balloon-shaped fullerene molecule, and from there they travel to the positive of the solar cell. This space left by electrons during the process is known as a hole. In order for the system to work, it must also move through the polymer on the other side of the equipment to complete the circuit.
After detecting that there, in the conductivity of the holes, the key lay, the scientists completed their redesign and, without resorting to solvent additives or heat treatments, they proposed a solution that improves the efficiency of this type of cells, to bring it to 9.12%.
The experts, who have just published the the results of your research, they are optimistic with this approach. And is that at a time of transition to the massive use of solar energy for consumption in homes, industries and devices of virtually any kind, its lead could be a nudge to move from the laboratory to the commercial phase. “That we were able to produce these cells without paying too much attention to the crystal structure of the polymer layers could enable us to mass-produce these equipments just by printing methods“. This is argued by the co-author of this research, Yoshio Aso, who anticipates that, if this stage is reached and the proposed plastic cells are extended, the costs of solar technology would be reduced very significantly.