First-Principles Study on the Stability and Electronic Properties of Dion–Jacobson Halide A′(MA)_n−1B_nX_3n+1 Perovskites

Abstract

Two-dimensional (2D) hybrid organic–inorganic perovskites have shown great application potential in solar cells and other optoelectronic devices. However, due to their wide band gap and limited stability, 2D perovskites can not be good candidates for solar cell application. To cover this gap, we propose a new system of the Dion–Jacobson (DJ) phase with divalent organic cations to obtain suitable band gaps and stronger stability. Based on first-principles calculation, we study the structure, stability, and electronic properties of a series of 2D DJ perovskites, which adopt the general formula A′A n–1B n X3n+1 (A′ = 1,4-phenylenedimethanammonium (PDMA) or 1,4-bis (aminomethyl)­cyclohexane (BAC) divalent organic cations, A = methylammonium (MA), B = Ge/Sn/Pb, X = Cl/Br/I, and n = 1–4). The structural stability and thermodynamic stability are analyzed through formation energy and ab initio molecular dynamics (AIMD). The results show that all A′(MA) n−1B n X3n+1 exhibit strong stability compared with their three-dimensional (3D) homologous perovskites. Besides, the AIMD shows that the perovskites still have a high stability at 600 K. Compared to the aliphatic cation BAC, the aromatic diammonium organic cation PDMA contributes to the conduction band and gradually decreases with the increase in the number of layers. The band gap decreases with the increase in the number of layers n and gradually approaches the three-dimensional (3D) band gap. This theoretical study should provide a theoretical basis for finding solar cells with excellent band gaps and improving the stability of the equipment.

Interlayer Charge Transport in 2D Lead Halide Perovskites from First Principles

“…The highest occupied crystalline orbital (HOCO) is primarily composed of the antibonding hybridization of the Pb 6s/I 5p orbitals. In contrast, the lowest unoccupied crystalline orbital (LUCO) is mainly made up of the nonbonding Pb 6p orbitals with a minor contribution from the I 5p orbitals in antibonding hybridization. , …”

“…In contrast, the lowest unoccupied crystalline orbital (LUCO) is mainly made up of the nonbonding Pb 6p orbitals with a minor contribution from the I 5p orbitals in antibonding hybridization. 64,65 Additional analyses of the MD trajectories at 300 K are reported in the SI. These refer to the interaction between the organic and inorganic components of the 2D perovskites, as analyzed following the rotational autocorrelation function of the C−N vector and the vibrational power spectrum (Figure S3).…”

Electronic and Photovoltaic Properties of Superlattices Constructed by Organic–Inorganic Perovskites: a Theoretical Perspective

“…Experimentally, organic–inorganic hybrid perovskites MAPbI 3 , FAPbI 3 , and MAPbI 2 Br are prepared from the precursors of PbI 2 , MAI, FAI, and MABr. − Mishra et al calculated the formation enthalpy of MAPbI 3 based on the reactants PbI 2 and MAI . Yao et al calculated the formation enthalpies of 2D and 3D A­(MA) n −1 B n X 3 n +1 perovskites to explore the structural stability of homologous perovskites. Hence, the formation enthalpies for (FAPbI 3 ) n /(MAPbI 3 ) 1 and (FAPbI 3 ) n /(MAPbI 2 Br) 1 can be computed from the precursors based on the formulas and . where E (FAI), E (MAI), E (MABr), and E (PbI 2 ) are the total energies of each component, respectively.…”

“…40−42 Mishra et al calculated the formation enthalpy of MAPbI 3 based on the reactants PbI 2 and MAI. 40 Yao et al 43 calculated the formation enthalpies of 2D and 3D A(MA) n−1 B n X 3n+1 perovskites to explore the structural stability of homologous perovskites. Hence, the formation enthalpies for (FAPbI 3 ) n / (MAPbI 3 ) 1 and (FAPbI 3 ) n /(MAPbI 2 Br) 1 can be computed from the precursors based on the formulas 2 and 3.…”

Divalent organic cations as a novel protective layer for perovskite materials

“…16 The 2D Dion-Jacobson (DJ) type PSs, which use divalent organic cations as the connector between two MAPbI 3 PS parts, could further improve the ambient stability. 17,18 The divalent cations connect the inorganic layers of two MAPbI 3 parts by electrostatic interaction, thus achieving a stronger connection and better performance of interlayer charge carrier transport compared with the 2D RP-type PSs. 19 Hang et al 20 researched the 1,5-pentane-diammonium (NH 3 (CH 2 ) 5 NH 3 ) based 2D DJtype PS ((NH 3 (CH 2 ) 5 NH 3 )(MA) 3 Pb 4 I 13 ), which is outstanding in photophysical properties and thermal stability.…”