Hybrid Halide Perovskites: Discussions on Terminology and Materials

Abstract

hybrid perovskites ·l ayered perovskites · lead and iodide deficient 3D hybrid perovskite · perovskites ·R uddlesden-Popper Abstract: Hybrid halide perovskites (HP) have emerged in the last decade as an ew class of semiconductors with superior performances in photovoltaic and electronic devices.T he literature about these halide semiconductors is abundant and al ot of names/expressions are used to define networks, structures,ormaterials.Inthis context, there is aneed to offer some discussions about the relevance of using the word "perovskite" and the associated expressions ("RP" (Ruddlesden-Popper), "DJ" (Dion-Jacobson), "ACI" (alternating cations in the interlayer space), "hexagonal perovskites", "hollow perovskites", "d-HP" (deficient 3D HP),…). Moreover,t he description of perovskite networks through elimination/substitution processes from the ABX 3 structure will be compared to the knownd imensional reduction concept.

Formamidinium‐Based Dion‐Jacobson Layered Hybrid Perovskites: Structural Complexity and Optoelectronic Properties

“…[1][2][3] However, these materials have shown limited stability against oxygen and water, [4][5][6] which has increased the interest in low-dimensional perovskite analogues. [7][8][9][10][11] Layered 2D perovskites incorporate hydrophobic organic cations between the hybrid perovskite slabs that are mainly defined by S 2 A n-1 Pb n X 3n+1 and S'A n-1 Pb n X 3n+1 formulations, where S and S' are mono-and bifunctional organic spacers, respectively, A is the organic cation in the perovskite slab (such as methylammonium (MA) or formamidinium (FA)), M is a divalent metal (mostly Pb 2+ ), and X is the halide anion (Cl -, Br -, or I -), while n defines the number of hybrid perovskite slabs. [9][10][11][12][13] It is worth noting that, although we refer to these formulations as low-dimensional perovskites in accordance with the conventional nomenclature, [8,9] some…”

“…of these materials might not strictly correspond to perovskite structures and they could be more appropriately denoted as perovskite-related structures. [10] In addition to their classification by the number of slabs (n = 1, 2, 3, etc. ), two main archetypes of layered perovskites are predominant to date, namely Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) systems.…”

“…), two main archetypes of layered perovskites are predominant to date, namely Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) systems. [9][10][11][12][13][14][15][16][17][18][19][20] The RP structural category is defined by the S 2 A n-1 Pb n X 3n+1 formulation, which comprises an organic double layer between the inorganic layers featuring an offset per unit cell of the perovskite slab. [9][10][11][12] The DJ systems are based on the S'A n-1 Pb n X 3n+1 compositions employing organic layers (S') that stack in an almost perfect alignment between unit cells, featuring smaller interlayer space.…”

Recent Progress in Engineering Metal Halide Perovskites for Efficient Visible‐Light‐Driven Photocatalysis

“…Considering the structural instability and intrinsic toxicity in 3 D lead‐based perovskites, extensive research has explored MHPs with other structures and compositions, such as lead‐free perovskites and low‐dimensional perovskites, such as AB 2 X 5 (see Figure d, also called 2 D perovskite), A 4 BX 6 (see Figure e, also called 0D perovskite), and double‐phase perovskites (A 2 B + B 3+ X 6 , see Figure f) . In particular, the lead‐free double‐phase Cs 2 AgBiBr 6 perovskite, showing a long photoluminescence (PL) lifetime (ca.…”

Rigid Amine‐Induced Pseudo‐3 D Lead‐Free Bismuth Halide Perovskite with an Improved Band Edge for Visible‐Light Absorption

“…Since the use of lead iodide perovskite in solar cells was reported in 2012, organometal halide perovskites have emerged as promising semiconductor materials owing to their excellent photovoltaic properties . In the past few years, the organometal halide perovskites APbX 3 , in which A represents an alkylamine positive ion, such as CH 3 NH 3 + and NH 2 CHNH 2 + and X=I, Br, or Cl, have proven to be good materials for the preparation of efficient perovskite solar cells .…”