Caffeine could hold the key to improving the thermal stability of perovskite solar cells and making them commercially viable, a study published on Thursday by Taiwanese scientist Yang Yang (楊陽) and his research team at the University of California, Los Angeles (UCLA) showed.
Perovskite solar cells are believed to be the future of solar power, because they are more energy efficient compared with traditional silicon solar cells and are cheaper to produce.
However, their poor thermal stability has kept them from being commercially viable, said Yang, who is professor of materials science and engineering at UCLA.
As they are constantly exposed to sunlight, solar cells need to have high thermal stability, Yang said.
On a coffee break last year, two students on Yang’s team came up with the idea of testing the thermal stability of caffeine in perovskite solar cells.
As caffeine boils at 300°C, which is significantly higher than the operational temperature of solar cells, Yang said that they decided to give it a try.
His team later discovered that the chemical structure in caffeine formed a strong bond with lead ions — the key material in perovskite solar cells — and that this improved how the cells operated.
The team found that adding caffeine to perovskite solar cells helped them maintain thermal stability for up to 1,300 hours, or about 55 days, while preserving 86 percent of the energy received from sunlight.
Perovskite solar cells made without caffeine only retained 60 percent of their energy after 175 hours, or about seven days, they found.
Yang said that caffeine was the first compound tested that showed positive results, although there might be others that are even more efficient, and that the increased stability could advance the commercialization of perovskite solar cells.
Their study titled “Caffeine improves the performance and thermal stability of perovskite solar cells” was published in the journal Joule.
Yang, who completed a bachelor’s in physics at National Cheng Kung University, earned a master’s in physics and applied physics in 1988 and a doctorate in 1992 from the University of Massachusetts Lowell.
Yang’s research focuses on solar energy and highly efficient electronic devices, according to his resume on the UCLA Web site.
Yang, has 331 refereed papers and 24 patents and has given more than 120 plenary, keynote and invited talks. Since 1997 he has supervised 42 doctoral students and 51 postdoctoral students, the Web site said.
A group of Taiwanese-American and Tibetan-American students at Harvard University on Saturday disrupted Chinese Ambassador to the US Xie Feng’s (謝鋒) speech at the school, accusing him of being responsible for numerous human rights violations. Four students — two Taiwanese Americans and two from Tibet — held up banners inside a conference hall where Xie was delivering a speech at the opening ceremony of the Harvard Kennedy School China Conference 2024. In a video clip provided by the Coalition of Students Resisting the CCP (Chinese Communist Party), Taiwanese-American Cosette Wu (吳亭樺) and Tibetan-American Tsering Yangchen are seen holding banners that together read:
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