@misc{GombolaHasemannKauffmannetal., author = {Gombola, C. and Hasemann, G. and Kauffmann, A. and Sprenger, I. and Laube, S. and Schmitt, A. and Gang, Florian and Bolbut, V. and Oehring, Michael and Blankenburg, Malte and Schell, Norbert and Staron, Peter and Pyczak, Florian and Kr{\"u}ger, Manja and Heilmaier, Martin}, title = {A zone melting device for the in-situ observation of directional solidification using high-energy synchrotron X-rays}, series = {Review of Scientific Instruments}, volume = {91}, journal = {Review of Scientific Instruments}, number = {9}, issn = {0034-6748}, pages = {9}, language = {en} } @misc{KediaDasKotetal., author = {Kedia, Mayank and Das, Chittaranjan and Kot, Malgorzata and Yalcinkaya, Yenal and Zuo, Weiwei and Tabah Tanko, Kenedy and Matvija, Peter and Ezquer, Mikel and Cornago, I{\~n}aki and Hempel, Wolfram and Kauffmann, Florian and Plate, Paul and Lira-Cantu, Monica and Weber, Stefan A.L. and Saliba, Michael}, title = {Mitigating the amorphization of perovskite layers by using atomic layer deposition of alumina}, series = {Energy \& environmental science}, volume = {18}, journal = {Energy \& environmental science}, number = {11}, publisher = {Royal Society of Chemistry (RSC)}, address = {London}, issn = {1754-5692}, doi = {10.1039/D4EE05703A}, pages = {5250 -- 5263}, abstract = {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.}, language = {en} }