Methylammonium tin iodide perovskite: structural, electronic and thermodynamic properties by a DFT study with different exchange–correlation functionals

Abstract

Lead-free perovskites have drawn much attention of researchers in the field of electronics and photovoltaics due to the toxicity issue of the lead halide perovskites. The methylammonium tin iodide CH 3 NH 3 SnI 3 amongst others has become a viable alternative due to its eco-friendliness, as well as narrower bandgap and its wider visible absorption spectrum. In this study different theoretical approaches were employed in investigating the structural, electronic and thermodynamic properties of the orthorhombic phase (O-phase) of the CH 3 NH 3 SnI 3 perovskite. By using the first-principle calculations with the density functional theory, a direct bandgap was determined at gamma symmetry points with three exchangecorrelation functionals: PBE 1.12 eV, PBEsol 0.98 eV, and LDA 0.46 eV. Based on the comparison of lattice constants and bandgaps with the experimental values, the best performance resulted from PBE. The decomposition of the CH 3 NH 3 SnI 3 perovskite into solid state products, CH 3 NH 3 I and SnI 2 , was considered; the enthalpy of the reaction Δ r H° (0 K) = 37 kJ mol −1 and enthalpy of formation of the O-phase perovskite Δ f H° (CH 3 NH 3 SnI 3 , 0 K) = − 390 kJ mol −1 were evaluated, indicating the stability of the O-phase CH 3 NH 3 SnI 3 at low temperature, in agreement with experimental findings.

Rational design of mixed Sn–Ge based hybrid halide perovskites for optoelectronic applications: a first principles study

“…[21][22][23] The crystallographic information le of DMASnI 3 (space group Pna2 1 ) have been obtained from materials project. [18][19][20] We have carried out the initial calculations using two different exchange correlation functionals viz. Perdew-Burke-Ernzerhof functional (PBE) and Perdew Burke Ernzerhof for solids (PBE sol ) and the convergence in case of plane wave cut-off, lattice parameters as well as the charge density cut-off is attained.…”

“…Perdew-Burke-Ernzerhof functional (PBE) and Perdew Burke Ernzerhof for solids (PBE sol ) and the convergence in case of plane wave cut-off, lattice parameters as well as the charge density cut-off is attained. [20][21][22]24 To validate the adopted methodology that we have employed through out the investigation, we have also carried out test SCF calculation for one reference compound (DMAPbI 3 ; whose lattice parameters and E g values are already reported) using four different functionals viz. PBE, PBEsol, PBE0 and HSE06 respectively.…”

“…We have obtained the crystallographic information les (CIF) of our studied compounds from the crystallography open database and Materials Project which are free databases for crystal structures. [18][19][20] The parent framework of the investigated compounds are provided in Fig. 1 and their optimized coordinates are provided in Table S1 in ESI.…”

Additive Effects of Guanidinium Iodide on CH3NH3PbI3 Perovskite Solar Cells

“…The band structures, effective masses, [ 42–44 ] and bandgaps were analyzed for the Brillouin zone of the perovskite crystal along the directions of the wave vector. Paths for the MA 0.875 GA 0.125 PbI 3 perovskite crystal were set as follows: Γ (0, 0, 0) → X (0, 1/2, 0) → M (1/2, 1/2, 0) → Γ→ R (1/2, 1/2, 1/2) → X | M → R .…”

“…Structure models for MAPbI 3 (a ¼ 6.277 Å) and MA 0.875 GA 0.125 PbI 3 (a ¼ 6.294 Å) with cubic symmetry were constructed using 2 Â 2 Â 2 supercells as the initial unit cells, and were utilized for the band calculation. The band structures, effective masses, [42][43][44] and bandgaps were analyzed for the Brillouin zone of the perovskite crystal along the directions of the wave vector. Paths for the MA 0.875 GA 0.125 PbI 3 perovskite crystal were set as follows:…”