Researchers at the University of Michigan have made a significant breakthrough in addressing the rapid degradation of perovskite semiconductors, a development that could potentially lead to solar cells that are two to four times less expensive than current thin-film solar panels. Perovskite solar cells, while more environmentally friendly than their silicon-based counterparts, suffer from a shorter lifespan due to degradation when exposed to heat, moisture, and air.
To enhance the stability and overall lifespan of perovskite solar cells, the researchers focused on identifying molecules that could prevent rapid degradation. They found that bulky “defect pacifying” molecules were particularly effective in increasing the stability of perovskite films. These molecules, when added to the perovskite crystals, prevented defects from forming at high temperatures, thus enhancing the material’s durability.
Credit: Zhengtao Hu, Gong Lab, University of Michigan
The researchers created three additives with different shapes and sizes, each containing similar chemical building blocks. Larger molecules, by mass, demonstrated better interaction with perovskite crystals, effectively preventing the formation of defects. However, the study also revealed that the size and configuration of the additives were crucial.
Bulky molecules were found to be the most effective, as they not only interacted strongly with perovskite but also forced the formation of larger perovskite grains during manufacturing. Larger grains resulted in lower densities of grain boundaries, reducing the areas where defects could form.
The discovery opens the possibility of creating more cost-effective and durable solar energy solutions by combining perovskites with silicon-based semiconductors, potentially surpassing the maximum theoretical efficiency of silicon solar cells; These findings provide valuable insights into designing additives for perovskite solar cells, moving away from time-consuming trial-and-error methods.
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