Structural stability and optoelectronic properties of tetragonal MAPbI₃ under strain

Abstract

ABSTARCTIn recent years, organic-inorganic hybrid perovskites have attracted wide attention due to their excellent optoelectronic properties in the application of optoelectronic devices. In the manufacturing process of perovskite solar cells, perovskite films inevitably have residual stress caused by non-stoichiometry components and the external load. However, their effects on the structural stability and photovoltaic performance of perovskite solar cells are still not clear. In this work, we investigated the effects of external strain on the structural stability and optoelectronic properties of tetragonal MAPbI3 by using the first-principles calculations. We found that the migration barrier of Iion increases in the presence of compressive strain and decreases with tensile strain, indicating that the compressive strain can enhance the structural stability of halide perovskites. In addition, the light absorption and electronic properties of MAPbI3 under compressive strain are also improved. The variations of the band gap under triaxial and biaxial strains are consistent within a certain range of strain, resulting from the fact that the band edge positions are mainly influenced by the Pb-I bond in the equatorial plane. Our results provide useful guidance for realizing the commercial applications of MAPbI3-based perovskite solar cells.2

Anisotropic In Situ Strain‐Engineered Halide Perovskites for High Mechanical Flexibility

“…For the CsPbBr 3 thin films (Figure 3e), the bond length of PbBr I and PbBr II in the ab plane (coincident with the direction of the in situ strain ε i ) was found to become shorter with a larger compressive stress while the bond lengths of PbBr III became elongated. As expected, the bond length of PbBr III in the apical plane (along the direction of film thickness) increased slightly with the compressive stress as an accompanying effect of the lateral contraction (also with the effect of Poisson's ratio [ 36 ] ). The opposite trends were observed in the case of the tensile strain for the CsPbBr 3 as anticipated.…”

“…The strain‐dependent structural changes were compared with the reported results for halide materials with the selected examples of M  X bond lengths as seen in Figure 4d. [ 36,43–47 ] The clear dependence of the bond length on the applied strain is very apparent by demonstrating the reduced bond lengths with the compressive strain. The reported differences in the bond length are based on the theoretical simulations incorporating the higher compressive or tensile strain values up to ≈10%.…”

The Role of Dimethylammonium in Bandgap Modulation for Stable Halide Perovskites

“…In the literature, experimental studies of octahedral tilt affecting the bandgap have been carried out on tin iodide perovskites, 2D Ruddlesden–Popper perovskites, and methylammonium lead halide in high-pressure environments. − The fact that we have observed similar effects by employing large-cation A-site substitution in 3D lead iodide-based perovskites represents a new mechanism for controlling their bandgap in regimes that are of interest for tandem devices. The extent to which the bandgap could be shifted in this way before a phase change would take place is yet unclear, but there is scope for many more combinations of cations to be tested.…”

Ferroic Halide Perovskite Optoelectronics

“…Meanwhile, the effect of strain on the optoelectronic properties and ion migration of MHPs has also been investigated. [ 152–167 ] Zhao et al. discovered that lattice strain significantly affects the stability of MHPs ( Figure a) via modifying the activation energy of ion migration; [ 152 ] a larger lattice strain reduces the activation of ion migration, promoting the degradation of CH 3 NH 3 PbI 3 films.…”