Abstract
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 C60 for the subsequent deposition of atomic layer deposition (ALD) SnO2, a commonly used electron contact bilayer for p-i-n devices. The enhanced nucleation results in a more continuous initial ALD SnO2 layer that exhibits superior barrier properties, protecting Cs0.25FA0.75Pb(Br0.20|0.80)3 films upon direct exposure to high temperatures (200 degrees C) and water. This surface modification with PEIE translates to more stable solar cells under aggressive testing conditions in air at 60 degrees 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 VOx films, demonstrating its potential to be broadly applied to other metal oxide contacts and device architectures.
Original language | American English |
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Number of pages | 9 |
Journal | Advanced Energy Materials |
Volume | 9 |
Issue number | 47 |
DOIs | |
State | Published - 2019 |
NREL Publication Number
- NREL/JA-5900-75614
Keywords
- atomic layer deposition
- barrier layer
- nucleation
- perovskite solar cells
- stability testing