Layered Hybrid Lead Iodide Perovskites with Short Interlayer Distances

Abstract

Layered hybrid perovskites comprise modular components that are individually highly tunable, resulting in materials with a range of structure and properties. In these layered materials, the usual assumption is of two-dimensional electronic behavior, because of the relatively large separations between the inorganic layers. Here, we report two layered hybrid lead iodide perovskites that possess unusually short interlayer distances: (IPA)2(MA)Pb2I7 and (ACA)(MA)PbI4 (IPA = iso-propylammonium, MA = methylammonium, ACA = acetamidinium). These compounds are prepared from mixing small organic cations, where they crystallize in the Ruddlesden-Popper type structure, and a structure with alternating cations in the interlayer space, respectively. The crystal structures are compared in detail with related structures, and electronic structures are analyzed using density-functional theory-based calculations. Time-resolved microwave conductivity measurements are employed to provide insight into charge transport in these compounds. This work exemplifies the unusual templating role of small organic cations in the layered halide compounds.

Dredging the Charge‐Carrier Transfer Pathway for Efficient Low‐Dimensional Ruddlesden‐Popper Perovskite Solar Cells

“…We try to explain this phenomenon from the perspective of lattice distortion (Note S2). As known, lattice strain arises when the spacer cations is too large or too small or in the presence of other interactions (such as hydrogen bonding) [37] . As a result, the (GABA) 2 MA n −1 Pb n I 3 n +1 system enables a neglected structural distortion (Figure S15), indicating larger perovskite flakes are needed to fully release the additional strain during spontaneous crystallization of (GABA) 2 MA n −1 Pb n I 3 n +1 .…”

Recent progress in layered metal halide perovskites for solar cells, photodetectors, and field-effect transistors

“…Recently, Mao and coworkers reported the ACI phase acetamidinium (ACA) perovskite single crystal, (ACA)(MA) PbI 4 . 50 The interlayer distance is about 3.22 Å, which is more compact than that of the (IPA)(MA)Pb 2 I 7 (separation distance of 5.15 Å) RP phase perovskite (Fig. 4e).…”

Two-Dimensional Hybrid Dion–Jacobson Germanium Halide Perovskites

“…22−26 The alternating cations in the interlayer space (ACI) types have also been reported, but with fewer examples. 27,28 The differences between these types originate from the choice of spacing organic/inorganic cations, with relatively different stacking of the layers. 19,22,28 The general formulas for the RP and DJ phases are A′ 2 A n−1 M n X 3n+1 and A′A n−1 M n X 3n+1 , respectively, where the larger spacing cation A′ is monovalent (+1) for the RP phases and divalent (+2) for the DJ phases.…”

“…So far, there are two main categories of (100)-oriented 2D halide perovskites reported, namely, Ruddlesden–Popper (RP) phases − and Dion–Jacobson (DJ) phases. − The alternating cations in the interlayer space (ACI) types have also been reported, but with fewer examples. , The differences between these types originate from the choice of spacing organic/inorganic cations, with relatively different stacking of the layers. ,, The general formulas for the RP and DJ phases are A′ 2 A n –1 M n X 3 n +1 and A′A n –1 M n X 3 n +1 , respectively, where the larger spacing cation A′ is monovalent (+1) for the RP phases and divalent (+2) for the DJ phases. The RP phases contain monovalent cations interdigitated between the adjacent inorganic layers, and the continuous inorganic layers are shifted with respect to each other by a half-unit cell. , In the case of DJ phases, they consist of short divalent spacer cations between the layers, and the inorganic layers stack exactly on top of each other.…”

“…27,28 The differences between these types originate from the choice of spacing organic/inorganic cations, with relatively different stacking of the layers. 19,22,28 The general formulas for the RP and DJ phases are A′ 2 A n−1 M n X 3n+1 and A′A n−1 M n X 3n+1 , respectively, where the larger spacing cation A′ is monovalent (+1) for the RP phases and divalent (+2) for the DJ phases. The RP phases contain monovalent cations interdigitated between the adjacent inorganic layers, and the continuous inorganic layers are shifted with respect to each other by a halfunit cell.…”