New phase transition in CsPbBr3

Abstract

Using a combination of in situ high-temperature X-ray diffraction and differential scanning calorimetry methods, the phase behavior of cesium lead bromide CsPbBr3 was investigated in the temperature range of (25–200) °C. In addition to the previously reported Pnma→P4/mbm and P4/mbm→Pm3-m phase transitions, a new fully reversible transition was found to occur between 45 °C and 57 °C. A novel phase, which is stable at least in the temperature range of (57–62) °C, has an orthorhombic structure with Cmcm space group, which makes the sequence of phase transitions upon heating the same for both CsPbBr3 and CsPbCl3 halides: Pnma→Cmcm→P4/mbm→Pm3-m.