New Metallic Ordered Phase of Perovskite CsPbI₃ under Pressure

Abstract

Pressure‐induced electronic structure transition from insulating phase to metal state is a potential new paradigm for halide perovskites. The metallization based on these materials may afford a novel motif toward realizing new electronic properties even superconductivity phenomenon. Herein, how static compression modulates the crystal and electronic structure of typical perovskite semiconductors cesium lead iodine (CsPbI 3 ) by both experimental and theoretical studies is reported. The comprehensive studies discover the insulator–metal transition of CsPbI 3 at 39.3 GPa, and reveal the key information behind the electronic transition. The perovskite's precise structural evolution is tracked upon compression, from orthorhombic Pnma phase to monoclinic C2/m structure before the metallic transition. More interestingly, the C2/m phase has the most distorted octahedra and the shortest Pb–I bond length relative to the average bond length that is ever reported in a halide perovskite structure. The electronic transition stems from the structural changes accompanied by the anomalously self‐distorted octahedra. These studies show that pressure can significantly alter the structural and electronic properties of these technologically important perovskites.

Strain Engineering for Tailored Carrier Transport and Thermoelectric Performance in Mixed Halide Perovskites CsPb(I1–xBrx)3

“…However, a dramatic increase of this contribution under a −8% compressive strain is observed, which is also reflected in Figure under a −8% strain, where the CBM is shown in green color as the I electrons contribute the most to it. This is similar to the pressure-induced electronic structure transition from the insulating phase to the metal phase reported in Liang et al , showing a noticeably enhanced I-5p orbital contribution in the CBM under 50 GPa.…”

Semiconductor to metallic transition under induced pressure in Cs2AgBiBr6 double halide perovskite: a theoretical DFT study for photovoltaic and optoelectronic applications

“…Applying a hydrostatic pressure to a material can easily tune the material's various properties. [13][14][15] L. Wang et al reported on the inuence of lead halide perovskite CH(NH 2 ) 2 PbBr 3 and found that the structural phase is changed at 2.2 GPa. 16 Pressuredependent samples undergo band-gap energy shrinkage and the electron orbits move toward the electric eld.…”

Emerging piezochromism in lead free alkaline earth chalcogenide perovskite AZrS3 (A = Mg, Ca, Sr and Ba) under pressure

“…The effect of exerting external pressure on perovskites and studying its effect on optoelectronic properties is a significant area of research. [36][37][38] Generally, within the same phase, upon compression, insulators and semiconductors show band gap decrement. This band gap decrement along with electron-electron correlations and electron-phonon coupling can also lead to metallization and eventually superconductivity.…”