Researchers at the National Renewable Energy Laboratory in the US have discovered how to make solar cells made with perovskite more efficient and stable. They combined a two-dimensional layer of the material with a three-dimensional one, achieving an actual energy gain of 16%.
This fusion between 2D and 3D layers can increase the effectiveness of perovskite solar panels to almost 25%. Most conventional photovoltaic devices manufactured today — made from silicon — have an average energy efficiency of less than 20% under normal use conditions.
“Perovskites belong to a family of materials with a specific crystalline structure, capable of absorbing visible and infrared sunlight, presenting a potential for high performance and low production cost. The problem is that this mineral has a very high instability when compared to silicon”, explains chemical engineer Kai Zhu, the main author of the study.
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To get around the instability problem, the scientists used a different 2D perovskite structure, known as Dion-Jacobson. This material is a metastable polymorph that has greater stability and a superior ability to move charge carriers freely.
Previous approaches used bulky organic cations or positively charged ions to increase the productivity of perovskite cells. However, this type of structure — known as the Ruddlesden-Popper — inhibited the movement of charge carriers, limiting their long-term effectiveness.
“The use of metastable 2D structures represents a promising new chemical project that can be adapted by industry to accelerate the development of more efficient and stable perovskite solar cells, reducing large-scale production costs,” adds Zhu.
During laboratory tests, the researchers compared a modified perovskite cell with a conventional control sample, without the combination of 2D and 3D layers. The results were encouraging, especially when compared to current systems for capturing sunlight.
The modified perovskite cell had a drop in energy efficiency of just 10% after the first thousand hours of continuous operation. Meanwhile, the panel manufactured with samples of the common material showed a reduction in power generation capacity of more than 43%.
“The expansion of the use of solar energy will require new technologies and tools that increase the flexibility of the network, transforming this modality into something economically viable and easily accessible. This new approach shows that it is possible to expand the capacity to generate renewable electricity without raising production costs”, concludes Kai Zhu.