Pressure‐Induced Perovskite‐to‐non‐Perovskite Phase Transition in CsPbBr ₃

The expanding range of optoelectronic applications lead-halide perovskites requires their production in diverse forms (single crystals, thin- and thick-films or even nanocrystals), motivating the development materials processing deposition routes that are specifically suited for these structurally soft, low-melting semiconductors. Pressure-assisted compact pellets gaining popularity, necessitating studies on pressure effects atomic structure properties resulting material. Herein we report phase transformation bulk polycrystalline cesium lead bromide from its three-dimensional perovskite (γ-CsPbBr3) into one-dimensional polymorph (δ-CsPbBr3) upon application hydrostatic (0.35 GPa). δ-CsPbBr3 is characterized by a wide bandgap 2.9 eV broadband yellow luminescence at 585 nm (2.1 eV) originating self-trapped excitons. formation was confirmed Raman spectroscopy, 207Pb 133Cs solid-state nuclear magnetic resonance, X-ray diffraction, absorption temperature-dependent time-resolved photoluminescence spectroscopy. No such transition observed colloidal CsPbBr3 nanocrystals.