Paper TF-MoA10
Synthesis of Gas Barrier Coatings for Hybrid Halide Perovskites by Atomic Layer Deposition

Monday, October 22, 2018, 4:20 pm, Room 104B

Atomic layer deposition of oxide film on shows a great promise to dramatically improve the ambient stability of hybrid halide perovskite. The nucleation of an ALD oxide on PCBM ([6,6]-phenyl-C61 butyric acid methyl ester) is critical to reliably apply this strategy. In this paper, we present the first study of the nucleation behaivor of ALD oxides, including Al₂O₃ and ZnO on PCBM. We find PCBM film acts a gas diffusion barrier blocking the ALD reactants (diethyl zinc) from etching the underlying CH₃NH₃PbI₃. However, ZnO is not able to nucleate on PCBM. We further identify that trimethyl aluminum, a strongly Lewis acid, reacts readily with C=O on PCBM to generate a seeding layer for nucleating ZnO ALD. This new chemical route is highly reliable and can be used to synthesize ALD ZnO coatings over PCBM. The synthesized PCBM/Al₂O₃-ZnO dramatically improves the stability of CH₃NH₃PbI₃ against the ambient and even against liquid water. The result signifies the importance of understanding of nulceation of ALD in enabling reliable barrier coatings for hybrid halide perovskite.