First principles study of 2D layered organohalide tin perovskites

Abstract

This article describes the structure and the electronic properties of a series of layered perovskites of a general formula (A+)2(SnX4)−2 where X = I, Br and A+ is an organic cation, either formamidinium, 1-methylimidazolium, or phenylethylammonium. For each system, two conformations are considered, with eclipsed or staggered stacking of the adjacent inorganic layers. Geometry optimizations are performed at the density functional theory level with generalized gradient approximation (GGA) functional and semiempirical correction for dispersion energies; band profiles and bandgaps are computed including both spin orbit coupling (SOC) and correlation (GW) effects through an additive scheme. The theoretical procedures are validated by reproducing the experimental data of a well known 3D tin iodide perovskite. The results, combined with the calculations previously reported on PbI4 analogues, allow us to discuss the effect of cation, metal, and halide substitution in these systems and in particular to explore the possibility of changing the electronic bandgap as required by different applications. The balance of SOC and GW effects depends on the chemical nature of the studied perovskites and strongly influences the value of the simulated bandgap.

Revealing the Chemistry between Band Gap and Binding Energy for Lead‐/Tin‐Based Trihalide Perovskite Solar Cell Semiconductors

“…[10a] Some recent studies have already startedr eferring to CH 3 NH 3 PbI 3 and its derivatives as "organohalide perovskites". [27][28][29][30] According to Varadwaj, [9] this is also misleading because the term organohalide strongly overlaps with the already established terminologyt hat readily refers to organohalide compounds as those containing ac arbon-halide covalent bond. [30][31][32][33][34][35] This means that organochlorides,o rganobromides, organoiodides, and so forth, which are halogen-substituted halocarbon compounds,a re organohalidec ompounds.…”

“…[27][28][29][30] According to Varadwaj, [9] this is also misleading because the term organohalide strongly overlaps with the already established terminologyt hat readily refers to organohalide compounds as those containing ac arbon-halide covalent bond. [30][31][32][33][34][35] This means that organochlorides,o rganobromides, organoiodides, and so forth, which are halogen-substituted halocarbon compounds,a re organohalidec ompounds. [30][31][32][33][34][35] Iodomethane (CH 3 I), chlorofluorocarbon compounds (CFCs), halogen-substituted benzene derivatives (e.g.,h exachlorobenzene), and others are common examples of organohalidec ompounds.S imilarly,a so rganometallic compounds (e.g.,o rganopalladium), organohalidec ompounds are also classified by prefixing the organic moiety with "organo-".…”

“…[30][31][32][33][34][35] This means that organochlorides,o rganobromides, organoiodides, and so forth, which are halogen-substituted halocarbon compounds,a re organohalidec ompounds. [30][31][32][33][34][35] Iodomethane (CH 3 I), chlorofluorocarbon compounds (CFCs), halogen-substituted benzene derivatives (e.g.,h exachlorobenzene), and others are common examples of organohalidec ompounds.S imilarly,a so rganometallic compounds (e.g.,o rganopalladium), organohalidec ompounds are also classified by prefixing the organic moiety with "organo-". The primary difference between these two types of compounds is that the former are coordination compounds, whereas the latter are halogen-substituted organic compounds.…”

2D Hybrid Halide Perovskites: Synthesis, Properties, and Applications

“…[168] An accurate argument is that the large organic cation can indirectly influence the bandgap via the geometric distortions of the inorganic octahedra, as shown from DFT calculations. [169] There are two types of bandgaps: direct and indirect. A directbandgap semiconductor has the conduction band minimum (CBM) and the valence band maximum (VBM) located at the same k-vector in the Brillouin zone, allowing for photon absorption and emission without a change in the momentum.…”

“…[ 168 ] An accurate argument is that the large organic cation can indirectly influence the bandgap via the geometric distortions of the inorganic octahedra, as shown from DFT calculations. [ 169 ]…”