Enhanced Stability of MAPbI₃ Perovskite Solar Cells using Poly(p-chloro-xylylene) Encapsulation

We demonstrated an effective poly(p-chloro-xylylene) (Parylene-C) encapsulation method for MAPbI₃ solar cells. By structural and optical analysis, we confirmed that Parylene-C efficiently slowed the decomposition reaction in MAPbI₃. From a water permeability test with different encapsulating materials, we found that Parylene-C-coated MAPbI₃ perovskite was successfully passivated from reaction with water, owing to the hydrophobic behavior of Parylene-C. As a result, the Parylene-C-coated MAPbI₃ solar cells showed better device stability than uncoated cells, virtually maintaining the initial power conversion efficiency value (15.5 ± 0.3%) for 196 h.