Protecting Perovskite Solar Cells against Moisture-Induced Degradation with Sputtered Inorganic Barrier Layers

We describe a general approach for protecting metal halide perovskite solar cells against degradation in high-humidity environments using a sputtered barrier coating. A SiO₂ protective layer, applied to two different types of perovskite solar cells, was deposited without strongly impacting the initial device performance. The degradation of the cells was imaged in real time using laser beam-induced current (LBIC) measurements in an accelerated test. We show that SiO₂ barrier films can improve the tolerance of the devices to extreme humidity conditions and extend lifetimes by a factor of ~60 when a 45 nm SiO₂ barrier layer is applied to CH₃NH₃PbI₃ and by a factor of ~600 when a 300 nm barrier is applied to a triple-cation perovskite material. The LBIC data revealed that the approach promises protection against degradation initiation at the edges of scribed lines, which will be necessary for the fabrication of monolithically integrated modules.