EPFL researchers are pushing the limits of perovskite solar cell performance by exploring the best way to grow these crystals. Michael Graetzel and his team found that, by briefly reducing the pressure while fabricating perovskite crystals, they were able to achieve the highest performance ever measured for larger-size perovskite solar cells, reaching over 20% efficiency and matching the performance of conventional thin-film solar cells of similar sizes. Their results are published in Science. This is promising news for perovskite technology that is already low cost and under industrial development. However, high performance in pervoskites does not necessarily herald the doom of silicon-based solar technology. Safety issues still need to be addressed regarding the lead content of current perovskite solar-cell prototypes in addition to determining the stability of actual devices. http://techxplore.com/news/2016-06-perovskite-solar-cells-surpass-percent.html Paper: http://science.sciencemag.org/content/early/2016/06/08/science.aaf8060
Perovskite Solar Cells Supercharge Electricity Production Even a relatively small initial supply of the new cells could bring solar power to remote locations that are not yet connected to any electrical grid. The silicon solar cells that currently dominate the world market suffer from three fundamental limitations. A promising new way of making high-efficiency solar cells, using perovskites instead of silicon, could address all three at once and supercharge the production of electricity from sunlight. Perovskites—a wide-ranging class of materials in which organic molecules made mostly of carbon and hydrogen bind with a metal such as lead and a halogen such as chlorine in a three-dimensional crystal lattice—can be made much more cheaply and with fewer emissions than silicon counterparts. Manufacturers can mix up batches of liquid solutions and then deposit the perovskites as thin films on surfaces of virtually any shape, no furnace needed. The film itself weighs very little, which eliminates the second big limitation of silicon solar cells, which is their rigidity and weight. Finally, the third major limitation of conventional solar cells is their power conversion efficiency, which has been stuck at 25 percent for 15 years. When they were first described, perovskites offered much lower efficiency. In 2009, perovskite cells made of lead, iodide and methylammonium converted less than 4 percent of the sunlight that hit them into electricity. But the pace of improvement in perovskites has been phenomenal, thanks in part to the fact that thousands of different chemical compositions are possible within this class of material. As posted above, by 2016, perovskite solar-cell efficiencies were above 20 percent—a five-fold improvement in just seven years and a stunning doubling in efficiency within just the past two years. They are now commercially competitive with silicon PV cells, and the efficiency limits of perovskites could be far higher still. http://www.scientificamerican.com/article/perovskite-solar-cells-supercharge-electricity-production/
Till now poor stability particularly in crucial outdoor environment has been a major show-stopper. But even there it's starting to look promising: http://pubs.rsc.org/en/content/articlelanding/2016/ee/c5ee02733k#!divAbstract
