Los Angeles, Caffeine may hold the key to making perovskite solar cells commercially viable by improving their thermal stability, according to the latest findings by American-based Taiwanese scientist Yang Yang and his research team at UCLA.
Perovskite solar cells are believed to be the future of solar power because they are more energy efficient when compared to traditional silicon solar cells and are cheaper to produce.
They have yet to be commercialized, however, because of their poor thermal stability, said Yang, the Carol and Lawrence E. Tannas Jr. endowed chair professor of materials science and engineering at UCLA.
Solar cells need to have high thermal stability because they are constantly exposed to sunlight, Yang said.
The idea of testing caffeine for thermal stability in perovskite solar cells was first conceived last year by two of his UCLA research students during coffee break, he said.
Because caffeine boils at 300 degree Celsius, which is significantly higher than the operational temperature of solar cells, Yang said they decided to give it a try.
His team later discovered that the chemical structure in caffeine forms a strong binding with lead ions the key material of perovskite solar cells and this chemistry was beneficial to the operation of the cells.
Researchers found that by adding caffeine to perovskite solar cells, the latter were able to maintain thermal stability for up to 1,300 hours, or about 55 days, while preserving 86 percent of the energy from sunlight.
Perovskite solar cells made without caffeine only retained 60 percent of their energy after 175 hours, or about seven days.
Yang said caffeine was the first compound tested by his team to have shown positive results, though there may be others that can work even more efficiently, and it could help push the commercialization of perovskite solar cells because of its stabilizing properties.
His study titled "Caffeine improves the performance and thermal stability of perovskite solar cells" conducted by Yang and his researchers was published Thursday by popular science journal Joule.
Yang, who received a bachelor of physics at National Cheng Kung University in Taiwan, received his master's degree in physics and applied physics at U-Mass, Lowell, in 1988 and a doctorate degree in the same subject at the same school in 1992.
According to his online resume at UCLA, Yang's major research interests are in the solar energy and highly efficient electronic devices.
He has more than 331 refereed-papers, 24 issued patents, and more than 120 plenary, keynote, and invited talks. Since 1997, he has supervised 42 Ph.D.s and 51 postdocs to completion. Among them, 25 have become tenure-track or tenured faculty.
Source: Focus Taiwan News Channel