Solar Power Technology Continues To Wait On the Promise Of Perovskite Cells

Scientists today are using perovskite materials, named after a little known 19th Century Russian mineralogist and nobleman Count Lev Perovski, to make solar cells more efficient and adaptable than ever before. The material was first discovered in Russia’s Ural Mountains in 1839 by Gustav Rose and became fairly common in later decades wherein it was found that some perovskites, like silicon, were semiconductors. In 2009, however, researchers discovered that perovskites could be used to build solar cells, which gave rise to the hope that they’d help us capitalise on the massive amounts of “freely” available solar power.

“Perovskites, I would argue, are one of the most exciting opportunities for solar cells in the immediate future,” said David Mitzi, a professor of Mechanical Engineering and Materials Science at Duke University, who has been studying the materials since the 1990s. He adds that perovskites can potentially both improve silicon solar cells, a 50-year old established technology, and compete with them since they can be manufactured into a variety of electricity-producing substances with ease, and at lower temperatures (meaning possibly lower costs) than their silicon counterparts. Though replacing silicon by perovskite will be possible only after due consideration is given to the latter material’s stability and durability.

While Perovskite cells ranked quite low vis a vis efficiency initially, their technology has improved quickly in recent years. “The efficiency with which solar cells that have these perovskite materials convert sunlight to electrons has increased at a really incredible rate, to the extent that now the efficiencies are close to those of silicon solar cells in the lab,” said Lynn Loo, a professor of chemical engineering at Princeton University and the director of the Andlinger Center for Energy and the Environment. “That’s why we are so excited about this class of materials.”

Since these cells can be made as thin sheets at low temperatures, or as inks to be “printed” onto underlying surfaces of other substances, say, flexible rolls of plastic, they can be used on surfaces where silicon cells aren’t practical to use, like the outer coverings of vehicles. Thin films of perovskites can be applied to the glass of windows, so that most of the sunlight can pass through them while a portion of it can be converted to electricity. But perhaps the most beneficial way to use perovskite cells is to combine them with silicon cells, allowing the former to use more solar energy than the latter. While the theoretical maximum efficiency of the best silicon cells at present, is about 29 percent, perovskite cells can be used to produce power from wavelengths of light unavailable to silicon cells, so it will be profitable to cover silicon solar cells with semi-transparent films of perovskite cells.

All the same, some challenges remain before Perovskite materials, one of them being their lack of durability on account of damage from moisture and humidity. Silicon cells, on the other hand, can be used for 25-30 years straight without these concerns. Clearly, Perovskite will have to overcome these challenges in order to play a significant role in the future of solar energy. Perhaps the $40 million allocation of funds by the Biden administration for the research and development of Perovskite materials, announced this March, is an indication of a hopeful future.