Room-Temperature Atomic Layer Deposition of Al2 O3 : Impact on Efficiency, Stability and Surface Properties in Perovskite Solar Cells

Abstract

In this work, solar cells with a freshly made CH₃ NH₃ PbI₃ perovskite film showed a power conversion efficiency (PCE) of 15.4 % whereas the one with 50 days aged perovskite film only 6.1 %. However, when the aged perovskite was covered with a layer of Al₂ O₃ deposited by atomic layer deposition (ALD) at room temperature (RT), the PCE value was clearly enhanced. X-ray photoelectron spectroscopy study showed that the ALD precursors are chemically active only at the perovskite surface and passivate it. Moreover, the RT-ALD-Al₂ O₃ -covered perovskite films showed enhanced ambient air stability.

Keywords: ALD; Al2O3; XPS; perovskite; solar cells.