Importance of tailoring lattice strain in halide perovskite crystals

Abstract

In this review paper, the residual strain of a polycrystalline halide perovskite film is systematically studied based on its structural inhomogeneity, which is closely correlated to the local carrier dynamics caused by a modulated electronic band structure. Long-range collective strain ordering is responsible for the overall structural properties, consequently determining the optoelectronic properties of the perovskite film. Notably, the perovskite phase stability is strongly affected by the internal strain, favoring a lower energy state. The important parameters affecting the residual strain in a real perovskite film, ranging from thermal stress to lattice mismatch and compositional inhomogeneity, are subsequently introduced along with their impacts on the optoelectronic properties and/or the stability of the crystals.

High-Efficiency (>14%) and Air-Stable Carbon-Based, All-Inorganic CsPbI2Br Perovskite Solar Cells through a Top-Seeded Growth Strategy

“…It is observed that when the Br-rich top surface perovskite layer was formed in the TSSG CsPbI 2 Br film, it induces the lattice contraction of the underlying CsPbI 2 Br, generating compressive strain on the underlying CsPbI 2 Br. It has been demonstrated that the phase stability of the CsPbI 2 Br materials is strongly related to their lattice strain. , Indeed, we found that the TSSG CsPbI 2 Br film prepared at 200 °C shows much greater stability than the control sample. As shown in Figure g, the TSSG CsPbI 2 Br film can retain its initial original color after being kept in ambient air with specified RH of 20–25% and at room temperature for 9 h, whereas the control sample began to turn yellow after ∼1 h.…”

“…Because the top surface perovskite layer of the TSSG CsPbI 2 Br film has greater Br – anion content, its lattice constant is smaller than that of the underlying CsPbI 2 Br. The compressive strain along the horizontal direction of the TSSG CsPbI 2 Br film is thus produced because of the lattice mismatch, ,, accounting for the shifts of the (100) and (200) XRD peaks of the TSSG CsPbI 2 Br films toward the higher angles, as observed in Figure b. To more clearly show the origin of the compressive strain in the TSSG CsPbI 2 Br film, we prepared a series of the TSSG CsPbI 2 Br films under the typical temperature of 200 °C based on the MABr/methanol solution with different concentrations.…”

Strain in perovskite solar cells: origins, impacts and regulation

“…S2b). The PL peak shifts from ∼1.532 eV under no strain to ∼1.488 eV under the compressive strain of −2.4%, indicating a reduction of ∼35 meV in the bandgap and demonstrating the feasible strain range for tuning the bandgap of perovskites from experiment [ 58 , 63 ]. Chen et al.…”

Efficient Gradient Potential Top Electron Transport Structures Achieved by Combining an Oxide Family for Inverted Perovskite Solar Cells with High Efficiency and Stability

“…As expected, we can observe that the PL decay lifetime (fitted with a biexponential decays model) is reduced from 9.6 ns of the pristine In 2 O 3 /perovskite sample to 7.4 ns of for the Sn:In 2 O 3 /perovskite sample and 5.8 ns of the Sn:In 2 O 3 /In 2 O 3 /perovskite sample. The results indicate a more efficient charge transfer for Sn:In 2 O 3 /In 2 O 3 bilayer ETL-based PSCs, , agreeing well with the PL spectra and the favorable energy band level. Charge extraction and recombination information can also be derived from the transient photocurrent and photovoltage (Figure S6a,b).…”