Organic–inorganic lead-iodide perovskites are attracting tremendous interest because of their great application potential in optoelectronics and photovoltaics. Despite extensive interest, however, no lead-iodide perovskites have been found as multiaxial multiferroic materials with the coexistence of full ferroelectricity and full ferroelasticity. Here, based on the ferroelastic [EQ]PbI3 (EQ = N-ethyl-quinuclidine) with an Aizu notation of 6/mmmF2/m, we introduced a hydroxyl group to N-ethyl-quinuclidine and successfully synthesized a homochiral lead-iodide perovskite multiaxial multiferroic [(R)-N-ethyl-3-quinuclidinol]PbI3 ([R-EQ]PbI3). [R-EQ]PbI3 undergoes a phase transition at 380 K from 622 to 2 point groups, and thereby it is a multiaxial full ferroelectric and also a multiaxial full ferroelastic in the room-temperature phase according to the Aizu notation of 622F2(s). Multiple equivalent ferroelectric/ferroelastic axes can endow [R-EQ]PbI3 with a larger polarization/strain in the polycrystalline samples. This work presents the first multiaxial full multiferroic in lead-iodide perovskites, which would inspire further exploration of chiral perovskite multiferroics for applications such as high precision microdisplacement devices and variable surface acoustic wave delay lines.
有机-无机
碘化铅包晶石因其在光电和光伏领域的巨大应用潜力而备受关注。然而,尽管人们对其兴趣浓厚,但还没有发现完全
铁电性和完全
铁弹性共存的多轴多
铁氧体材料。在此,我们以具有
铁弹性的[EQ]PbI3(EQ = N-乙基
奎宁环)(会津符号为 6/mmmF2/m)为基础,在 N-乙基
奎宁环中引入羟基,成功合成了同手性
碘化铅包晶石多轴多
铁性[(R)-N-乙基-3-
奎宁环醇]PbI3([R-EQ]PbI3)。[R-EQ]PbI3 在 380 K 时经历了从 622 点基团到 2 点基团的相变,因此根据 622F2(s)的会津符号,它是一种多轴全
铁电体,在室温相中也是一种多轴全
铁弹性体。在多晶样品中,多个等效
铁电/
铁弹性轴可使[R-EQ]PbI3 具有更大的极化/应变。这项研究首次提出了
碘化铅包晶石的多轴全多
铁性,这将激励人们进一步探索手性包晶石多
铁性的应用,如高精度微位移器件和可变表面声波延迟线。