Browsing by Author "Hinderhofer, Alexander"

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    Elucidating Structure Formation in Highly Oriented Triple Cation Perovskite Films
    (Weinheim : Wiley-VCH, 2023) Telschow, Oscar; Scheffczyk, Niels; Hinderhofer, Alexander; Merten, Lena; Kneschaurek, Ekaterina; Bertram, Florian; Zhou, Qi; Löffler, Markus; Schreiber, Frank; Paulus, Fabian; Vaynzof, Yana
    Metal halide perovskites are an emerging class of crystalline semiconductors of great interest for application in optoelectronics. Their properties are dictated not only by their composition, but also by their crystalline structure and microstructure. While significant efforts are dedicated to the development of strategies for microstructural control, significantly less is known about the processes that govern the formation of their crystalline structure in thin films, in particular in the context of crystalline orientation. This work investigates the formation of highly oriented triple cation perovskite films fabricated by utilizing a range of alcohols as an antisolvent. Examining the film formation by in situ grazing-incidence wide-angle X-ray scattering reveals the presence of a short-lived highly oriented crystalline intermediate, which is identified as FAI-PbI2-xDMSO. The intermediate phase templates the crystallization of the perovskite layer, resulting in highly oriented perovskite layers. The formation of this dimethylsulfoxide (DMSO) containing intermediate is triggered by the selective removal of N,N-dimethylformamide (DMF) when alcohols are used as an antisolvent, consequently leading to differing degrees of orientation depending on the antisolvent properties. Finally, this work demonstrates that photovoltaic devices fabricated from the highly oriented films, are superior to those with a random polycrystalline structure in terms of both performance and stability.
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    From Chalcogen Bonding to S–π Interactions in Hybrid Perovskite Photovoltaics
    (Weinheim : Wiley-VCH, 2024) Luo, Weifan; Kim, SunJu; Lempesis, Nikolaos; Merten, Lena; Kneschaurek, Ekaterina; Dankl, Mathias; Carnevali, Virginia; Agosta, Lorenzo; Slama, Vladislav; VanOrman, Zachary; Siczek, Miłosz; Bury, Wojciech; Gallant, Benjamin; Kubicki, Dominik J.; Zalibera, Michal; Piveteau, Laura; Deconinck, Marielle; Guerrero‐León, L. Andrés; Frei, Aaron T.; Gaina, Patricia A.; Carteau, Eva; Zimmermann, Paul; Hinderhofer, Alexander; Schreiber, Frank; Moser, Jacques‐E.; Vaynzof, Yana; Feldmann, Sascha; Seo, Ji‐Youn; Rothlisberger, Ursula; Milić, Jovana V.
    The stability of hybrid organic–inorganic halide perovskite semiconductors remains a significant obstacle to their application in photovoltaics. To this end, the use of low-dimensional (LD) perovskites, which incorporate hydrophobic organic moieties, provides an effective strategy to improve their stability, yet often at the expense of their performance. To address this limitation, supramolecular engineering of noncovalent interactions between organic and inorganic components has shown potential by relying on hydrogen bonding and conventional van der Waals interactions. Here, the capacity to access novel LD perovskite structures that uniquely assemble through unorthodox S-mediated interactions is explored by incorporating benzothiadiazole-based moieties. The formation of S-mediated LD structures is demonstrated, including one-dimensional (1D) and layered two-dimensional (2D) perovskite phases assembled via chalcogen bonding and S–π interactions. This involved a combination of techniques, such as single crystal and thin film X-ray diffraction, as well as solid-state NMR spectroscopy, complemented by molecular dynamics simulations, density functional theory calculations, and optoelectronic characterization, revealing superior conductivities of S-mediated LD perovskites. The resulting materials are applied in n-i-p and p-i-n perovskite solar cells, demonstrating enhancements in performance and operational stability that reveal a versatile supramolecular strategy in photovoltaics.