Most solar panels today use silicon wafers to create electricity. Using perovskite instead of silicon lowers the cost of solar panels two ways. First, the material itself is less expensive than silicon. Second, the manufacturing process uses much less energy than is needed to make silicon-based solar panels. Even though perovskite panels are not quite as efficient as those that use silicon wafers, they reportedly have the shortest “energy payback time” of any panel. Simply put, the energy used to produce them is regained from generation faster than with any other type of solar PV panel.
Up until now, making perovskite solar panels has involved the use of highly toxic chemicals — a significant drawback. But scientists at Oxford University in Britain say they have developed a much less toxic solvent system. The new process should clear the way for large-scale commercial production of perovskite solar cells.
“At the moment, there are three main solvents used in the manufacture of perovskite solar cells, and they are all toxic, which means you wouldn’t want to come into contact with them,” explains Nakita Noel from Oxford University’s Department of Physics. “Additionally, the most efficient perovskite solar cells are currently made through a process called solvent quenching – a technique that is not easily transferred from lab-scale deposition techniques to large-scale deposition techniques.
“While vapor deposition of these materials can overcome this problem, it will come at additional costs. One of the main selling points of this material is that it is cheap and can be easily solution-processed. We have now developed the first clean, low boiling point, low viscosity solvent for this purpose,” he says. “What is really exciting about this breakthrough is that largely reducing the toxicity of the solvent hasn’t led to a reduction in the efficiency of the material in harnessing solar energy.”
By combining methylamine and acetonitrile, the scientists were able to develop a clean solvent that quickly crystallizes perovskite films at room temperature and can be used to help coat large solar panels with the material. The scientists’ report has been published in the journal Energy & Environmental Science.
In recent years, perovskite-based solar cells have raced to the forefront of photovoltaic technology. They are able to compete in efficiency with well established solar technologies such as inorganic thin-film and multi-crystalline silicon used in solar panels around the world.
One advantage of perovskite cells is they can be engineered to react to different wavelengths of light. Eventually, that may make them more efficient than silicon-based solar cells as well as less expensive. If so, perovskite solar panels could drive the cost of solar power even lower than the record low prices established recently in Chile and Abu Dhabi. Once that happens, generating electricity by burning fossil fuels will be closer to becoming a thing of the past.
