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Enhanced Nucleation of Atomic Layer Deposited Contacts Improves Operational Stability of Perovskite Solar Cells in Air
Author(s) -
Raiford James A.,
Boyd Caleb C.,
Palmstrom Axel F.,
Wolf Eli J.,
Fearon Benjamin A.,
Berry Joseph J.,
McGehee Michael D.,
Bent Stacey F.
Publication year - 2019
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201902353
Subject(s) - materials science , atomic layer deposition , nucleation , halide , layer (electronics) , perovskite (structure) , bilayer , diffusion barrier , chemical engineering , polyethylenimine , nanotechnology , optoelectronics , oxide , metal , inorganic chemistry , chemistry , transfection , biochemistry , organic chemistry , membrane , engineering , metallurgy , gene
Metal‐halide perovskites show promise as highly efficient solar cells, light‐emitting diodes, and other optoelectronic devices. Ensuring long‐term stability is now a major priority. In this study, an ultrathin (2 nm) layer of polyethylenimine ethoxylated (PEIE) is used to functionalize the surface of C 60 for the subsequent deposition of atomic layer deposition (ALD) SnO 2 , a commonly used electron contact bilayer for p–i–n devices. The enhanced nucleation results in a more continuous initial ALD SnO 2 layer that exhibits superior barrier properties, protecting Cs 0.25 FA 0.75 Pb(Br 0.20 I 0.80 ) 3 films upon direct exposure to high temperatures (200 °C) and water. This surface modification with PEIE translates to more stable solar cells under aggressive testing conditions in air at 60 °C under illumination. This type of “built‐in” barrier layer mitigates degradation pathways not addressed by external encapsulation, such as internal halide or metal diffusion, while maintaining high device efficiency up to 18.5%. This nucleation strategy is also extended to ALD VO x films, demonstrating its potential to be broadly applied to other metal oxide contacts and device architectures.