Effective hole extraction using MoOx-Al contact in perovskite CH3NH3PbI3 solar cells

Abstract

We report an 11.4%-efficient perovskite CH₃NH₃PbI₃ solar cell using low-cost molybdenum oxide/aluminum (i.e., MoO_x/Al) as an alternative top contact to replace noble/precious metals (e.g., Au or Ag) for extracting photogenerated holes. The device performance of perovskite solar cells using a MoO_x/Al top contact is comparable to that of cells using the standard Ag top contact. Analysis of impedance spectroscopy measurements suggests that using 10-nm-thick MoO_x and Al does not affect charge-recombination properties of perovskite solar cells. Using a thicker (20-nm) MoO_x layer leads to a lower cell performance caused mainly by a reduced fill factor. Our results suggest that MoO_x/Al is promising as a low-cost and effective hole-extraction contact for perovskite solar cells.