The National Institute of Materials Science in Japan has developed a lightweight solar cell capable of generating electricity for more than 1,000 continuous hours with a photoelectric conversion of more than 20%. We tell you more about her.
We have already told you in the past about perovskite, the material that promises to revolutionize solar energy thanks to its interesting qualities.
Perovskite is a mineral belonging to the group of oxides which was discovered by the German geologist Gustav Rose. Its name was designated in honor of the Russian mineralist Lev Alekseyevich von Perovski.
Advantages and disadvantages of perovskite
The scientific community also calls a perovskite group of crystals that have a structure similar to that of calcium titanate. This stands out for offering a high conversion of solar energy into electricity.
Thanks to this, perovskite solar panels have great potential and have additional advantages that have made it, for many, the future technology.
They are easier and cheaper to manufacture. They also allow transparent and flexible panels of good quality. However, they also offer some disadvantages, mainly their propensity for degradation in the presence of water moleculeswhich limits its duration and efficiency.
The definitive perovskite cell
A group of researchers from Japan National Institute of Materials Science claims to have fixed the problems limiting the growth of perovskite solar panels.
According to reported in a statementhave developed a durable 1 cm2 perovskite solar cell capable of generating electricity for more than 1000 hours without interruptionand with a photoelectric conversion efficiency of more than 20% when exposed to sunlight.
Because this solar cell can be made on the surface of a plastic material at about 100°C, «this technique can be used to develop lightweight and versatile solar cells»reports the NIMS.
Most perovskite solar cells have similar power generation mechanisms. When the perovskite layer absorbs sunlight, it generates electrons and holes.
These electrons and holes then migrate separately to the adjacent electron transport layer and hole transport layer. They flow in them to produce an electric current.
In order to simultaneously improve the efficiency and durability of perovskite solar cells, these layers and the interfaces between them must allow electrons and holes to move through them more freely. At the same time, must enable interfaces to be impermeable to water molecules.
To achieve this, the NIMS team added to the interface between the electron transport layer and the perovskite layer a hydrazine derivative containing water-repellent fluorine atoms.
This interface successfully prevented water molecules that had penetrated the electron transport layer from coming into contact with the perovskite layer, thereby improving the durability of the solar cell.
Greater efficiency and durability
Likewise, the use of this interface also made it possible to reduce the amount of crystalline defects which formed on the surface of the perovskite layer, a cause of decreased power generation efficiency.
Additionally, the team added a phosphonic acid derivative to the interface between the hole transport layer and the perovskite layer, which minimized defect formation in the hole transport layer. As a result, the power generation efficiency of the solar cell also improved.
According to the Japanese research team, the plan for the future is to “develop even more efficient and durable perovskite solar cells by creating a database of molecules that can be integrated into the interface, conducting research based on data and the design of molecules that can be used to improve interfacial properties.”
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Photos: NIMS