Solar cells enhanced with caffeine. Credit: Rui Wang and Jingjing Xue
Imagine caffeine giving a boost to solar cells. The inspiration is now a reality and it all started with Rui Wang sharing this during a coffee break jokingly with Jingjing Xue, a fellow graduate student in the engineering department of the University of California, Los Angeles that they should caffeinate their experimental solar cells to make them work better.
The idea helped them discover a promising alternative to traditional solar cells, which are more efficient at converting light to electricity. And, their research has been published recently in the journal Joule which is expected to enable this cost-effective renewable energy technology to compete on the market with silicon solar cells.
In Yang’s lab, the research team had been working on augmenting the lifespan of an unstable but promising type of solar panel made from a material called perovskite, which laced panels with stabilizing compounds. This is in the backdrop that in the last decade, perovskite research panels have greatly improved in efficiency, going from harvesting 1% of available solar energy to 20%. Also, if perovskite is to provide future solar energy, then researchers would need a way to stabilize the cells for the long term.
This is where caffeine plays an important role. Yang explains that when [the caffeine] locks onto the perovskite crystal, it stabilizes the grain boundaries and prevents the material from degrading and the solar cell has much better stability. To test the idea, the researchers ran a molecular analysis on that cell and found caffeine bound to the lead atoms of perovskite. They also tested it and found it could run stably for around 1,300 hours, apart from which it had better efficiency than the decaf panel to boot.
Yang stated that tandem or hybrid solar cells that are made with two different types of perovskite had been able to reach around 30% efficiency before any caffeine boost. Meanwhile, Jinsong Huang, a physicist at the University of North Carolina, Chapel Hill reiterated that the study was impressive. He added that solar cells could be made more efficient and more stable in other ways. However, the result was good and it also helped to open our minds about different materials that one would never have thought that it would work.
In the context, Joseph Berry, a physicist at the National Renewable Energy Lab in Golden, Colorado shared that the study could also help researchers find solutions on manipulating and engineering perovskite in ways that might steer future research.