Phase transitions, screening and dielectric response of CsPbBr₃

Abstract

<p>Structural transformations of CsPbBr₃ were studied by multiple techniques (dielectric, Raman, EPR spectroscopy and XRD) in an extended temperature range.</p>

The Temperature Dependence of the Photoluminescence of CsPbBr3 Nanocrystals Reveals Phase Transitions and Homogeneous Linewidths

“…In the bulk CsPbBr 3 example, the low temperature transition at 361 K is known to be first order . However, bulk-like nanocrystals may be different from the single crystal CsPbBr 3 .…”

“…In the bulk CsPbBr 3 example, the low temperature transition at 361 K is known to be first order. 40 However, bulk-like nanocrystals may be different from the single crystal CsPbBr 3 . One report using PL(T) showed no obvious discontinuity in the band gap between 100 and 500 K in CsPbBr 3 .…”

Soft Perovskite-Type Antiferroelectric with Giant Electrocaloric Strength near Room Temperature

“…For example, a series of symmetry breaking has been verified in CsPbBr 3 , changing from the cubic phase (Pm3̅ m) to tetragonal (P4/mbm) and even to a lower orthorhombic space phase (Pnma). 14 Emphatically, the more striking characteristic is that the central Cs + cation prefers relative displacements under external stimuli such as light, heat, and pressure, which would create an antiparallel alignment of dipoles. 15 Consequently, the preferable motions of Cs + as well as the octahedral nature make the {CsPb 2 Br 7 }-based motifs a promising platform for realizing antiferroelectricity.…”

“…This structural feature might afford a driving force to trigger successive phase transitions. For example, a series of symmetry breaking has been verified in CsPbBr 3 , changing from the cubic phase ( Pm 3̅ m ) to tetragonal ( P 4/ mbm ) and even to a lower orthorhombic space phase ( Pnma ) . Emphatically, the more striking characteristic is that the central Cs + cation prefers relative displacements under external stimuli such as light, heat, and pressure, which would create an antiparallel alignment of dipoles .…”

Stepwise Dielectric Switching Occurs in Two Photo-Responsive Complexes Possessing Two-Dimensional Structures

“…In some special molecular materials, the dielectric constant can be shifted between the low- and high-value states corresponding to a variation of the molecular degree of freedom of polar components . One typical molecular structure is perovskite (ABX 3 ), where the dielectric switching can be achieved by an order–disorder structural change of organic cations confined in a framework composed of metal centers and short bridging ligands such as CN – , HCOO – , N 3 – , and halide anions. − For example, an exceptional dielectric switching is observed in a molecular compound (Himd) 2 [KFe­(CN) 6 ] (Himd + = imidazolium) as a consequence of frozen–thawed structural changes of the Himd + organic cations encapsulated in perovskite cavities formed by CN – ligands and metal centers . A dozen of molecular materials that demonstrate thermally controlled dielectric switching have been synthesized in the past few years .…”