Kot, M.; Kegelmann, L.; Das, C.; Kus, P.; Tsud, N.; Matolinova, I.; Albrecht, S.; Matolin, V.; Schmeisser, D.: Room Temperature Atomic Layer Deposited Al2O3 Improves the Efficiency of Perovskite Solar Cells over Time. ChemSusChem 11 (2018), p. 3640-3648
10.1002/cssc.201801434

Abstract:
Electrical characterisation of perovskite solar cells consisting of room‐temperature atomic‐layer‐deposited aluminium oxide (RT‐ALD‐Al2O3) film on top of a methyl ammonium lead triiodide (CH3NH3PbI3) absorber showed excellent stability of the power conversion efficiency (PCE) over a long time. Under the same environmental conditions (for 355 d), the average PCE of solar cells without the ALD layer decreased from 13.6 to 9.6 %, whereas that of solar cells containing 9 ALD cycles of depositing RT‐ALD‐Al2O3 on top of CH3NH3PbI3 increased from 9.4 to 10.8 %. Spectromicroscopic investigations of the ALD/perovskite interface revealed that the maximum PCE with the ALD layer is obtained when the so‐called perovskite cleaning process induced by ALD precursors is complete. The PCE enhancement over time is probably related to a self‐healing process induced by the RT‐ALD‐Al2O3 film. This work may provide a new direction for further improving the long‐term stability and performance of perovskite solar cells.