Andrzej Nowok, Mirosław Mączka, Anna Gągor, Maciej Ptak, Jan K. Zaręba, Daria Szewczyk, Swaroop Palai and Adam Sieradzki*,
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引用次数: 0
Abstract
Hybrid organic–inorganic halides have traditionally been viewed as materials that adopt well-ordered structural phases at low temperatures. In this article, we report a one-dimensional perovskitoid aminoguanidinium lead iodide (AGAPbI3) with a first-order phase transition at 400/369 K (during heating/cooling) that breaks away from this rule. Specifically, we demonstrate that the structural transformation to the low-temperature monoclinic C2/c phase does not entirely suppress the motions associated with the organic AGA+ cation, leading to a phenomenon which we call now a persistent disorder. Indeed, it is still possible to observe pronounced dynamics of its terminal NH2 group at least, which gradually slows down upon cooling and impacts the PbI64– octahedra. As a result, we observe an unusually high activation energy of 0.6 eV related to the low-temperature relaxation dynamics, which is approximately 1 order of magnitude higher than those observed in conventional hybrid halides. We illustrate that the ongoing dynamic processes profoundly influence the temperature-dependent third-harmonic generation response and photoluminescence, the latter of which is characterized by two broad emission peaks with large Stokes shifts. Lastly, we emphasize that AGA+ cations can adopt two symmetry-equivalent positions within the low-temperature phase of AGAPbI3, revealing the ongoing transition between the low-temperature static and high-temperature dynamic disorder types in this hybrid compound.
期刊介绍:
The journal Chemistry of Materials focuses on publishing original research at the intersection of materials science and chemistry. The studies published in the journal involve chemistry as a prominent component and explore topics such as the design, synthesis, characterization, processing, understanding, and application of functional or potentially functional materials. The journal covers various areas of interest, including inorganic and organic solid-state chemistry, nanomaterials, biomaterials, thin films and polymers, and composite/hybrid materials. The journal particularly seeks papers that highlight the creation or development of innovative materials with novel optical, electrical, magnetic, catalytic, or mechanical properties. It is essential that manuscripts on these topics have a primary focus on the chemistry of materials and represent a significant advancement compared to prior research. Before external reviews are sought, submitted manuscripts undergo a review process by a minimum of two editors to ensure their appropriateness for the journal and the presence of sufficient evidence of a significant advance that will be of broad interest to the materials chemistry community.