UNIVERSITY PARK, Pa. — Borrowing from cell membranes, the protective barriers around cells in all living organisms, Penn State scientists have developed a new, cost-effective method for creating bio-inspired solar devices that could improve the performance of next-generation solar technology.
The researchers combined perovskite solar cell material — named for their unique crystalline structure that excels at absorbing visible light — with a synthesized version of natural lipid biomolecules to help protect against moisture-induced degradation. These biomolecules are fatty or waxy materials produced by our bodies don’t dissolve in water, like cholesterol, and are a major component of cell membranes. The biomolecules formed a membrane-like layer around the perovskite, boosting stability and efficiency in tests. The approach may have a transformative impact on how perovskite solar cells are designed, the scientists reported in the journal Advanced Energy Materials.
“Lipid molecules are naturally very good against moisture and cannot dissolve in water,” said Yuchen Hou, who conducted this research while a doctoral student in the Department of Materials Science and Engineering at Penn State. “We take a molecule that’s evolved for many millions of years in nature with specific functions, and we see if the material can have the same function in our artificial device.”
Perovskites are a promising solar cell technology because they exceed the efficiency of traditional silicon, according to Hou. But the material quickly degrades when exposed to moisture — like humidity in the air — and prior attempts to create protective layers have meant sacrificing efficiency and increasing costs, the scientists said.
With the new method, the biomolecules formed a nano-thin layer around the perovskite, protecting it from the elements and improving its lifespan. According to Hou, the method is cheaper and easier than conventional fabrication methods for silicon solar cells and still results in a material with good electrical properties, allowing them to make large devices without sacrificing efficiency or how much sunlight the cells can convert to electricity.
“In this work we are trying to solve two major problems in the field of perovskite solar cells — efficiency and stability,” said Luyao Zheng, a postdoctoral scholar in the Department of Material Science and Engineering at Penn State and co-author on the study. “I think the major achievement here is that we were able to make a very large module with really good uniformity across the large area, and we’ve also been able to maintain a very good efficiency as well as stability.”