New eco-friendly perovskite: a step toward clean energy without compromise

Researchers from the University of Wisconsin–Madison, the National Renewable Energy Laboratory, and other partner institutions have made a major breakthrough in solar energy by developing a new tin-perovskite-based material with built-in protection against environmental exposure. This innovation could become a key factor in the mass adoption of environmentally safe solar cells.

The problem of toxicity and the search for alternatives

For a long time, the solar industry has faced the challenge of using toxic materials, including lead, in the production of solar panels. Despite major gains in efficiency, the risk of harmful substances leaking into the environment when panels are damaged or discarded remained a serious obstacle to a full transition to solar energy. Scientists have been actively searching for environmentally safe alternatives, and perovskites, especially tin-based ones, have become some of the most promising candidates.

Tin perovskites demonstrate excellent light-absorbing properties and efficient electrical charge transport, which makes them attractive for use in solar cells. However, earlier versions of these materials had a major drawback: poor resistance to air and moisture. Under the influence of oxygen and water, they degraded quickly, losing their functional properties. This problem became the main barrier to the commercialization of eco-friendly tin-based solar cells.

“Molecular raincoat” for solar cells

The new development, dubbed a “molecular raincoat,” involves a molecular redesign of the material that gives it built-in protection from external factors. This was achieved by integrating protective properties directly into the microscopic structure of the material rather than by adding bulky external layers.

“We wanted to find a way to protect these materials while preserving the properties that make them attractive for use in solar cells,” explains Song Jin, a chemistry professor at the University of Wisconsin–Madison.

The researchers experimented with different halogen atoms, such as fluorine, chlorine, and bromine, modifying the material’s organic components. The key step was creating a mixed heterostructure of two-dimensional and three-dimensional (2D/3D) components.

The unexpected effect of dense packing

During experiments involving a chlorinated version of the material, a surprising effect was discovered. The perovskite crystals began to pack much more tightly than before. This dense atomic packing created a kind of “molecular shield” that physically blocked water and oxygen from reaching the sensitive parts of the solar cell.

“Such dense atomic packing works like a molecular shield. Water and oxygen cannot penetrate inside, creating a protective barrier that keeps them away from the solar cells,” the researchers note.

This structural change not only improved the material’s durability but also positively affected its efficiency. The new chlorinated tin perovskite showed impressive stability, retaining its integrity for months in open air. It even withstood several days of full immersion in water without any signs of dissolution. Theoretical models confirmed that the dense molecular structure effectively blocks the penetration of oxygen and water to the vulnerable tin core.

Efficiency and durability: a new standard

To evaluate the practical viability of the developed material, the team created working solar cells in collaboration with researchers from the National Renewable Energy Laboratory. The devices showed a power conversion efficiency of 16.2%, one of the highest values for tin-based solar cells.

Even more impressive are the durability results. After 1600 hours in dry air, the cells retained more than 95% of their initial output. Under extreme conditions — continuous simulated sunlight at 55 °C — the cells retained 80% of their output after 1000 hours of operation.

“Previously, developing solar cells mostly meant having to choose between efficiency and durability. This material shows that companies do not necessarily have to make that trade-off,” the researchers emphasize.

“The most exciting part is that a relatively small change in material design delivers such a major improvement in stability,” says Christopher T. Triggs, one of the study’s first authors. “It shows how designing organic components and controlling how perovskite structures pack can provide powerful protection for the resulting perovskite materials from the environment.”

Commercial potential and the future

Recognizing the significant commercial potential of a lead-free and durable solar cell, the Wisconsin Alumni Research Foundation and the National Renewable Energy Laboratory jointly filed a patent application for the technology. The study was published in the prestigious scientific journal Nature Materials, underscoring its high scientific significance.

This development opens new prospects for clean energy, making it not only environmentally safe but also more reliable and cost-effective. The possibility of creating solar panels that do not require toxic materials and can withstand challenging operating conditions is an important step toward energy independence and protecting the environment for future generations. The growth of solar energy based on such innovations could significantly accelerate the global shift to a sustainable energy model, reducing dependence on fossil fuels and their negative impact on the climate.