Researchers at Cornell University have made a breakthrough in solar cell technology, developing a new type of perovskite material that is both highly efficient and remarkably durable.
Perovskites are a special class of crystalline materials known for their ability to turn sunlight into electricity.
They have the potential to create lightweight, low-cost solar cells that could outperform traditional silicon-based models.
However, most perovskites are prone to breaking down when exposed to heat, moisture, and sunlight, limiting their practical use.
The research team at Cornell tackled this problem by creating a new two-dimensional (2D) perovskite layer that acts as a protective coating for a three-dimensional (3D) perovskite solar cell.
This innovative design was detailed in a study published on May 9 in the journal Joule.
The researchers found that by layering this 2D perovskite on top of the 3D one, they could significantly increase the cell’s resistance to weather conditions, such as heat and humidity, while also boosting its performance.
In the past, scientists tried using a compound called methylammonium (MA) to create 2D protective layers.
While MA-based perovskites had good efficiency, they were highly unstable and began to break down after just a few hundred hours of sunlight exposure.
Attempts to replace MA with formamidinium (FA), a more stable compound, faced challenges too. FA’s larger size created too much strain in the material, making it difficult to form stable 2D layers.
The Cornell team discovered a solution through a process called “lattice matching.” This concept involves finding a perfect fit between the 2D and 3D perovskite structures.
They selected special organic molecules, known as ligands, that naturally align with the FA cage and the surrounding crystal structure.
This allowed the researchers to build a stable 2D layer that fit seamlessly with the 3D perovskite, avoiding the usual strain and instability.
Lead researcher Shripathi Ramakrishnan explained that the key was finding a ligand that did not compress the material too much, allowing the larger FA molecule to fit comfortably inside the structure.
This balance resulted in a protective coating that not only resisted breakdown under sunlight and heat but also improved the flow of electrical charges between the two layers.
When tested, the new 2D-on-3D perovskite solar cells achieved an impressive sunlight-to-electricity conversion rate of 25.3%. Even after nearly 50 days of exposure to intense light and heat, the cells lost only 5% of their efficiency.
This level of stability and performance marks a major step forward for perovskite technology, which has long struggled with durability issues.
Senior author Qiuming Yu, a professor of chemical and biomolecular engineering at Cornell, believes that perovskites could reach the commercial success of silicon-based solar cells with continued research.
While silicon solar panels have been developed for over 50 years, perovskites have had far less time for advancement. According to Yu, understanding the material at the molecular level will accelerate its path to commercialization.
Ramakrishnan’s internship at the National Renewable Energy Laboratory in Colorado also gave him insight into how these materials could perform under real-world conditions.
His experience reinforced the potential for perovskites to change the landscape of solar energy, making it more efficient and durable for everyday use.
