Ultrathin Aluminum Oxide Layers for Encapsulation of Perovskite Solar Cells

As perovskite solar cells advance along the path to commercialization, encapsulation has emerged as an important area of research. Low-cost, impermeable packaging is required for these devices to realize their full potential. This research demonstrates the development of an ultrathin, 50 nm, aluminum oxide layer deposited atop of perovskite solar cells with atomic layer deposition. Variation of oxidizing agents within the process as well as the deposition temperature were tested to optimize the barrier’s resilience against moisture ingress. The combinations of Al2O3 deposition variables were then tested to calculate their water vapor transmission rates, or WVTR. With the WVTR data showing that the inclusion of ozone as an oxidizer and high deposition temperatures optimize the barrier’s impermeability, compatibly with the perovskite solar cells themselves was studied. After optimization, a T80 of more than 1,000 hours was demonstrated for a perovskite solar cell encapsulated with the ultrathin aluminum oxide. This work allows for ultrathin encapsulation of perovskite solar cells without the addition of excessive weight while demonstrating extended performance in accelerated testing parameters.