A hybrid fluoride layered perovskite, (enH₂)MnF₄

Abstract

The title compound represents the first example of a hybrid layered fluoride perovskite.

Structural chemistry of layered lead halide perovskites containing single octahedral layers

“…(3) Out-of-phase tilt around the ab plane: X 3 + (RP); M 5 + (DJ). A thorough study of the possible combination of tilt modes in DJ phases was given by Aleksandrov & Bartolomé (2001) and a briefer version, in the context of hybrid systems by Li, Clulow et al (2019). Layer-shift modes in these systems are described by symmetry-lowering to monoclinic or triclinic (strain modes, À 5 + for example).…”

“…Note that we do not use the superscript notation for the c axis in the case of layered perovskites with single octahedral layers (as Glazer's original concept explicitly relies on octahedra being linked in the third direction). We use 'c' to mean 'rotated perpendicular to the layer direction' and c 0 to mean 'no rotation' (Li, Clulow et al, 2019). The symbol (Àc) is used if the second layer is rotated contrary to the first (which is only really relevant if there is a partial layer shift from the ideal RP parent).…”

Structural variations in (001)-oriented layered lead halide perovskites, templated by 1,2,4-triazolium

“…In fact, all our further attempts to reproduce the "T2PbBr4" composition, based on reaction mixtures of slightly different composition, produced T2PbBr4-I, but not T2PbBr4-II, supporting the suggestion that the former may be the more thermodynamically stable polymorph under such reaction conditions. Considering the octahedral tilting within the two polymorphs, the various options have been classified for A2BX4 RP phases and ABX4 DJ phases by Aleksandrov et al 19 , and in adapted Glazer-like notation by Li et al 20 In the notation of Li et al 20 the tilt system of T2PbBr4-II is aac, signifying rotation of octahedra around the a-axis and out-of-phase tilting of adjacent octahedra along each of the in-plane axes. This tilt system is analogous to the well-known 'GdFeO3-type' tilt system in conventional 3D perovskites and also appears to be relatively common in LHPs.…”

Three New Lead Iodide Chain Compounds, APbI3, Templated by Molecular Cations

“…The study of perovskite-related materials has grown tremendously in recent years [1] due to their enormous chemical and structural diversity and excellent physical properties, for example, ferroelectricity, luminescence, or magnetism [2][3][4]. In particular, lead(II) halide perovskites show impressive performances in their electronic and photophysical properties [5], making them promising candidates for practical applications such as solar cells [6,7] and light-emitting devices (LEDs) [8,9].…”

“…α-CsPbI 3 , for instance, exhibits a suitable bandgap (Eg =~1.7 eV), and is an excellent candidate for photovoltaic applications [10][11][12]. The general formula for perovskites is ABX 3 , where A is a large cation, B is a smaller cation, and X is an anion. However, there are many families of "perovskite-related" materials, which contain, for example, layered structural units derived from the archetypal "cubic" perovskite structure [5].…”