TY - GEN A1 - Gombola, C. A1 - Hasemann, G. A1 - Kauffmann, A. A1 - Sprenger, I. A1 - Laube, S. A1 - Schmitt, A. A1 - Gang, Florian A1 - Bolbut, V. A1 - Oehring, Michael A1 - Blankenburg, Malte A1 - Schell, Norbert A1 - Staron, Peter A1 - Pyczak, Florian A1 - Krüger, Manja A1 - Heilmaier, Martin T1 - A zone melting device for the in-situ observation of directional solidification using high-energy synchrotron X-rays T2 - Review of Scientific Instruments Y1 - 2020 SN - 0034-6748 SN - 1089-7623 VL - 91 IS - 9 ER - TY - GEN A1 - Kedia, Mayank A1 - Das, Chittaranjan A1 - Kot, Malgorzata A1 - Yalcinkaya, Yenal A1 - Zuo, Weiwei A1 - Tabah Tanko, Kenedy A1 - Matvija, Peter A1 - Ezquer, Mikel A1 - Cornago, Iñaki A1 - Hempel, Wolfram A1 - Kauffmann, Florian A1 - Plate, Paul A1 - Lira-Cantu, Monica A1 - Weber, Stefan A.L. A1 - Saliba, Michael T1 - Mitigating the amorphization of perovskite layers by using atomic layer deposition of alumina T2 - Energy & environmental science N2 - Atomic layer deposition of aluminum oxide (ALD-Al2O3) layers has recently been studied for stabilizing perovskite solar cells (PSCs) against environmental stressors, such as humidity and oxygen. In addition, the ALD-Al2O3 layer acts as a protective barrier, mitigating pernicious halide ion migration from the perovskite towards the hole transport interface. However, its effectiveness in preventing the infiltration of ions and additives from the hole-transport layer into perovskites remains insufficiently understood. Herein, we demonstrate the deposition of a compact ultrathin (∼0.75 nm) ALD-Al2O3 layer that conformally coats the morphology of a triple-cation perovskite layer. This promotes an effective contact of the hole transporter layer on top of the perovskite, thereby improving the charge carrier collection between these two layers. Upon systematically investigating the layer-by-layer structure of the PSC, we discovered that ALD-Al2O3 also acts as a diffusion barrier for the degraded species from the adjacent transport layer into the perovskite. In addition to these protective considerations, ALD-Al2O3 impedes the transition of crystalline perovskites to an undesired amorphous phase. Consequently, the dual functionality (i.e., enhanced contact and diffusion barrier) of the ALD-Al2O3 protection enhanced the device performance from 19.1% to 20.5%, while retaining 98% of its initial performance compared to <10% for pristine devices after 1500 h of outdoor testing under ambient conditions. Finally, this study deepens our understanding of the mechanism of ALD-Al2O3 as a two-way diffusion barrier, highlighting the multifaceted role of buffer layers in interfacial engineering for the long-term stability of PSCs. Y1 - 2025 U6 - https://doi.org/10.1039/D4EE05703A SN - 1754-5692 VL - 18 IS - 11 SP - 5250 EP - 5263 PB - Royal Society of Chemistry (RSC) CY - London ER -