Scientists have developed a new type of perovskite solar cell that combines impressive efficiency with long-lasting performance, marking an important step toward cheaper and more powerful solar energy.
The new design reached a power conversion efficiency of 27.3% while maintaining more than 90% of its original performance after 770 hours of continuous operation.
The research was carried out by a team at the Helmholtz-Zentrum Berlin (HZB) in Germany and has been published in the journal Joule.
Perovskite materials have attracted worldwide attention because they can convert sunlight into electricity very efficiently.
They are also much less expensive to produce than traditional silicon solar cells and are extremely lightweight. These advantages make them promising for future applications, including flexible solar panels that could be used on buildings, vehicles, and portable electronic devices.
Instead of using just one light-absorbing layer, the HZB team built a triple-junction solar cell. This design stacks three different perovskite materials on top of each other.
Each layer is designed to absorb a different part of the sunlight spectrum, allowing the cell to capture more solar energy and produce more electricity than a single-layer device.
Building such a complex structure is challenging because every layer must work smoothly with the next. One of the biggest difficulties is creating the connection between the middle and bottom layers, where electrical charges need to move efficiently without losing energy.
The researchers focused on improving this critical connection. In many perovskite solar cells, a material called PEDOT:PSS is used to help transport positive electrical charges. However, this material absorbs some light that could otherwise be converted into electricity and also reduces the long-term stability of the solar cell.
To solve this problem, the scientists tested a new combination of materials. They used a very thin layer of graphene oxide beneath a self-assembled monolayer, or SAM. A SAM is made of large organic molecules that naturally arrange themselves into a single, well-organized layer.
The researchers found that the graphene oxide created a much better surface for the SAM to sit on. Together, the two layers formed a more efficient pathway for electrical charges to travel through the solar cell. At the same time, the new design reduced energy losses that normally occur inside the device.
The results were impressive. The new solar cell achieved an efficiency of 27.3%, making it one of the best-performing all-perovskite triple-junction solar cells ever reported. Even more importantly, it proved to be highly durable. After more than 770 hours of continuous operation, the device still retained over 90% of its original efficiency, setting a new stability record for this type of solar cell.
The research team believes this is only the beginning. They say that by further improving the quality of the perovskite layers and the connecting films, future versions of the technology could exceed 30% efficiency.
Although more work is needed before these solar cells become commercially available, the study shows that perovskite technology continues to make rapid progress.
With higher efficiency, lower manufacturing costs, lighter weight, and greater durability, these next-generation solar cells could play a major role in expanding clean energy and helping reduce the world’s dependence on fossil fuels.
