Overcoming Perovskite Solar Cells' Instability Issues

Bill Gates’ Breakthrough Energy Venture is backing CubicPV, a perovskite solar tandem manufacturer. Perovskite is a common crystal structure that was discovered to induce electric charge in 2009. Contrary to silicon cells, perovskite cells do not need to be perfectly aligned, which makes it possible to layer onto different surfaces and produce electricity. They are also lightweight, requiring 20 times less material to produce than silicon cells. 

Photo credit: The Korea Herald 

In addition to standalone perovskite cells, a perovskite layer can be applied to silicon cells, creating perovskite tandem cells. The perovskite layer, with a bandgap of 1.7 eV, utilizes the higher-frequency photons that silicon cells may waste. As a result, perovskite tandem cells achieve their best efficiency of 29.1%, while perovskite cells’ efficiency can go up to 26.1%, according to data recorded from the National Renewable Energy Laboratory. 

With higher efficiency and lower cost, perovskite solar cells have their drawbacks. Perovskite solar cells degrade quickly when exposed to high temperatures and the interplay of oxygen and water molecules.  With the main focus of research activity for more than a decade being on lead halide perovskite, another concern of perovskite solar cells is the lead that they contain. Once a panel breaks and gets rained upon, it can lead to environmental problems such as decreased biodiversity and reproductive rates. 

Coating perovskite cells to prevent contact with water is an approach to increase their stability, however, the material used (phenethylammonium iodide) exhibits poor thermal stability. Thermal instability issues are also inherited because of Sn-Pb perovskites’ insufficient thermal transfer. Research found that incorporating carboranes into perovskite can effectively transfer heat and lower the surface temperature by 5 °C under illumination. 

The lightweight, flexible, and cost-effective nature of perovskite solar cells makes them an intriguing option for space technology applications. Perovskite solar cells retain their efficiency after being exposed to harsh conditions in space. Manufacturing perovskite solar cells in space can also eliminate the impact of moisture and oxygen on degradation. This is a great interest of NASA and includes additive manufacturing and in-space recycling for long-duration space missions.