Park Jae Yong, Mihalyi-Koch Willa, Triggs Christopher T, Roy Chris R, Sanders Kyana M, Wright John C, Jin Song
Department of Chemistry, University of Wisconsin-Madison, Madison, WI, 53706, USA.
Adv Mater. 2024 Jul;36(29):e2314292. doi: 10.1002/adma.202314292. Epub 2024 May 9.
2D hybrid organic-inorganic halide perovskites emerge as a new class of 2D semiconductors with the potential to combine excellent optoelectronic properties with symmetry-enabled properties such as ferroelectricity. Although many lead-based ferroelectric 2D halide perovskites are reported, there is yet to be a conclusive report of ferroelectricity in tin-based 2D perovskites. Here, the structures and properties of a new series of 2D Dion-Jacobson (DJ) Sn perovskites: (4AMP)SnI, (4AMP)(MA)SnI, and (4AMP)(FA)SnI (4AMP = 4-(aminomethyl)piperidinium, MA = methylammonium, and FA = formamidinium), are reported. Structural characterization reveals that (4AMP)SnI is polar with in-plane spontaneous polarization whereas (4AMP)(MA)SnI and (4AMP)(FA)SnI are centrosymmetric. Further, (4AMP)SnI displays second harmonic generation (SHG) and polarization-electric field hysteresis measurements confirm it is ferroelectric with a spontaneous polarization of 10.0 µC cm at room temperature. (4AMP)SnI transitions into a centrosymmetric structure above 367 K. As the first direct experimental observation of the spontaneous ferroelectric polarization of a Sn-based 2D hybrid perovskite, this work opens up environmentally friendly 2D tin halide perovskites for ferroelectricity and other physical property studies.
二维有机-无机卤化物钙钛矿作为一类新型二维半导体材料崭露头角，有望将优异的光电特性与诸如铁电性等基于对称性的特性相结合。尽管已报道了许多基于铅的铁电二维卤化物钙钛矿，但锡基二维钙钛矿中铁电性的最终报告仍未出现。在此，报道了一系列新型二维狄龙-雅各布森（DJ）锡钙钛矿：(4AMP)SnI、(4AMP)(MA)SnI 和 (4AMP)(FA)SnI（4AMP = 4-(氨甲基)哌啶鎓，MA = 甲基铵，FA = 甲脒鎓）的结构与性质。结构表征表明，(4AMP)SnI 具有面内自发极化，呈极性，而 (4AMP)(MA)SnI 和 (4AMP)(FA)SnI 是中心对称的。此外，(4AMP)SnI 表现出二次谐波产生（SHG），极化-电场滞后测量证实其在室温下具有 10.0 µC cm 的自发极化，是铁电体。(4AMP)SnI 在 367 K 以上转变为中心对称结构。作为对锡基二维杂化钙钛矿自发铁电极化的首次直接实验观测，这项工作为铁电性及其他物理性质研究开辟了环境友好型二维卤化锡钙钛矿材料。
