Atomic Layer Deposited Electron Transport Layers in Efficient Organometallic Halide Perovskite Devices

Amorphous TiO 2 and SnO 2 electron transport layers (ETLs) were deposited by low-temperature atomic layer deposition (ALD). Surface morphology and x-ray photoelectron spectroscopy (XPS) indicate uniform and pinhole free coverage of these ALD hole blocking layers. Both mesoporous and planar perovskite solar cells were fabricated based on these thin films with aperture areas of 1.04 cm 2 for TiO 2 and 0.09 cm 2 and 0.70 cm 2 for SnO 2 . The resulting cell performance of 18.3 % power conversion efficiency (PCE) using planar SnO 2 on 0.09 cm 2 and 15.3 % PCE using mesoporous TiO 2 on 1.04 cm 2 active areas are discussed in conjunction with the significance of growth parameters and ETL composition.