TY - GEN A1 - Kot, Małgorzata A1 - Kegelmann, Lukas A1 - Köbler, Hans A1 - Vorokhta, Mykhailo A1 - Escudero, Carlos A1 - Kúš, Peter A1 - Šmíd, Břetislav A1 - Tallarida, Massimo A1 - Albrecht, Steve A1 - Abate, Antonio A1 - Matolínová, Iva A1 - Schmeißer, Dieter A1 - Flege, Jan Ingo T1 - In situ Near-Ambient Pressure X-ray Photoelectron Spectroscopy Reveals the Influence of Photon Flux and Water on the Stability of Halide Perovskite T2 - ChemSusChem N2 - For several years, scientists have been trying to understand the mechanisms that reduce the long‐term stability of perovskite solar cells. In this work, we examined the effect of water and photon flux on the stability of CH3NH3PbI3 perovskite films and solar cells using in situ near‐ambient pressure X‐ray photoelectron spectroscopy (NAP‐XPS), field emission scanning electron microscopy (FESEM), and current density–voltage (J–V) characterization. The used amount of water vapor (up to 1 mbar) had a negligible impact on the perovskite film. The higher the photon flux, the more prominent were the changes in the NAP‐XPS and FESEM data; also, a faster decline in power conversion efficiency (PCE) and a more substantial hysteresis in the J‐V characteristics were observed. Based on our results, it can be concluded that the PCE decrease originates from the creation of Frenkel pair defects in the perovskite film under illumination. The stronger the illumination, the higher the number of Frenkel defects, leading to a faster PCE decline and more substantial hysteresis in the J‐V sweeps. KW - field emission scanning electron microscopy (FESEM) KW - Frenkel defects KW - near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) KW - perovskite KW - photon-induced degradation Y1 - 2020 U6 - https://doi.org/10.1002/cssc.202001527 SN - 1864-5631 SN - 1864-564X VL - 13 IS - 21 SP - 5722 EP - 5730 ER - TY - GEN A1 - Zuo, Weiwei A1 - Malekshahi Byranvand, Mahdi A1 - Kodalle, Tim A1 - Zohdi, Mohammadreza A1 - Lim, Jaekeun A1 - Carlsen, Brian A1 - Friedlmeier, Theresa Magorian A1 - Kot, Małgorzata A1 - Das, Chittaranjan A1 - Flege, Jan Ingo A1 - Zong, Wansheng A1 - Abate, Antonio A1 - Sutter‐Fella, Carolin M. A1 - Li, Meng A1 - Saliba, Michael T1 - Coordination Chemistry as a Universal Strategy for a Controlled Perovskite Crystallization T2 - Advanced Materials N2 - The most efficient and stable perovskite solar cells (PSCs) are made from a complex mixture of precursors. Typically, to then form a thin film, an extreme oversaturation of the perovskite precursor is initiated to trigger nucleation sites, e.g., by vacuum, an airstream, or a so-called antisolvent. Unfortunately, most oversaturation triggers do not expel the lingering (and highly coordinating) dimethyl sulfoxide (DMSO), which is used as a precursor solvent, from the thin films; this detrimentally affects long-term stability. In this work, (the green) dimethyl sulfide (DMS) is introduced as a novel nucleation trigger for perovskite films combining, uniquely, high coordination and high vapor pressure. This gives DMS a universal scope: DMS replaces other solvents by coordinating more strongly and removes itself once the film formation is finished. To demonstrate this novel coordination chemistry approach, MAPbI3 PSCs are processed, typically dissolved in hard-to-remove (and green) DMSO achieving 21.6% efficiency, among the highest reported efficiencies for this system. To confirm the universality of the strategy, DMS is tested for FAPbI3 as another composition, which shows higher efficiency of 23.5% compared to 20.9% for a device fabricated with chlorobenzene. This work provides a universal strategy to control perovskite crystallization using coordination chemistry, heralding the revival of perovskite compositions with pure DMSO. KW - Perovskite solar cells KW - nucleation KW - dimethyl sulfide ()DMS) solvent KW - coordination chemistry Y1 - 2023 U6 - https://doi.org/10.1002/adma.202302889 SN - 0935-9648 SN - 1521-4095 VL - 35 IS - 39 ER -