High Members of the 2D Ruddlesden-Popper Halide Perovskites: Synthesis, Optical Properties, and Solar Cells of (CH3(CH2)3NH3)2(CH3NH3)4Pb5I16

Abstract

Here, we present the fifth member (n = 5) of the Ruddlesden-Popper (CH 3 (CH 2) 3 NH 3) 2 (CH 3 NH 3) nÀ1 Pb n I 3n+1 family, which we successfully synthesized in high yield and purity. Phase purity could be clearly determined from its X-ray powder diffraction patterns, which feature the (0k0) Bragg reflections at low 2q angles. The obtained pure n = 5 compound was confirmed to be a direct bandgap semiconductor with E g = 1.83 eV. The direct nature of the band gap is supported by density functional theory calculations. Intense photoluminescence was observed at room temperature at 678 nm arising from the band edge of the material. High-quality thin films can be prepared by the hot-casting method from solutions with a pure-phase compound as a precursor. The planar solar cells fabricated with n = 5 thin films demonstrate excellent power-conversion efficiency of 8.71% with an impressive open-circuit voltage of $1 V. Our results point to the use of layered perovskites with higher n numbers and pure chemical composition.

Enhancing High Humidity Stability of Quasi‐2D Perovskite Thin Films through Mixed Cation Doping and Solvent Engineering

“…MA/FAbased quasi-2D perovskite has high humidity resistivity, remaining intact after 90 days under 60% relative humidity without encapsulation. Intermediate dihydrate phase typically seen in quasi-2D systems [27,47,48] and PbI 2 residues were not detected after MCD. Computational analysis was used to understand binding energies of cation mixture in solution and formation energies of mixed cations inside (MA) 1-x (FA) x PbI 3 perovskites.…”

New Type of 2D Perovskites with Alternating Cations in the Interlayer Space, (C(NH2)3)(CH3NH3)nPbnI3n+1: Structure, Properties, and Photovoltaic Performance

“…[1][2][3][4][5][6][7][8] Unlike the more extensively studied three-dimensional (3D) AMX 3 where the possibility of a 3D stable crystal structure is limited by the size and shape of the A + cation [9][10] the lower-dimensional perovskite semiconductors offer a much higher degree of structural versatility and permit better control and fine-tuning of the optoelectronic properties. 11 Conceptually, upon "cutting" the 3D parent compound along a specific crystallographic plane, infinite nanosheets with a slab thickness of atomic or molecular size can be obtained, which are separated by organic cations acting as spacers and in this context, they can be considered as natural quantum wells (QWs).…”

“…What effectively determines this crystallographic cut is the size and shape of the spacer cation. Cations employed for this purpose to date include, but not limited to, ammonium, 1,6,[12][13][14][15] amidinium, [16][17] imidazolium 18 and phosphonium 19 ions. Among the <100> perovskites, the Ruddlesden-Popper (RP) perovskites, [20][21] are by far the most common structural type with less common types being the Dion-Jacobson (DJ), [22][23] and Aurivillius (AV) [24][25][26] phases both of which finding paradigms only in oxide perovskite families.…”

Effects of transition metals incorporated into perovskite crystals on the electronic structures and magnetic properties by first-principles calculation

“…Control of the perovskite crystal structure and the chemical composition ratio using organic cations from methylammonium (MA = CH 3 NH 3 + ), formamidinium [FA = CH 3 (NH 2 ) 2 + ] [1,2], cesium (Cs) [3], guanidinium [4], divalent metals (lead, tin and bismuth) [5] and halogen anions (Cl − , Br − , and I − ) [6, 7, 8] is important factor for optimizing with tuning the photovoltaic and optical properties. The effects of halogen using bromide, iodide and chloride halides, amino cations, and hole-transporting layers on photovoltaic and optical properties were examined [4, 9, 10, 11].…”