Ultrasonic Velocity around the Successive Phase Transition Points of CsPbBr<sub>3</sub>

Hirotsu, Shunsuke; Suzuki, T.; Sawada, Shozo

doi:10.1143/jpsj.43.575

Cited by 40 publications

(15 citation statements)

References 13 publications

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“…10 Some of the older structural studies refer to the room temperature phase of CsPbBr3 as monoclinic 13,14,[17][18][19] whereas other studies, including more recent ones, consider an orthorhombic crystal structure. 10,15,20,21 The lattice parameters of orthorhombic and monoclinic phases are quite similar, with monoclinic descriptions reporting γ angles of 89.65°1 4 or 89.39°1 7 and hence deviating only slightly from an orthorhombic crystal structure. The ternary phase diagram of Cs-Pb-Br shows that not only CsPbBr3, but also CsPb2Br5 and Cs4PbBr6 are stable phases that can be grown reproducibly, using different ratios of CsBr and PbBr2 with similar synthesis conditions.…”

Section: Structural Properties Of Binary and Ternary Compounds In Thementioning

confidence: 90%

Spatial Phase Distributions in Solution-Based and Evaporated Cs–Pb–Br Thin Films

Caicedo‐Dávila

Funk

Lovrinčić³

et al. 2019

J. Phys. Chem. C

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In recent years, inorganic cesium-lead-halide perovskites, CsPbX3 (X=I, Br, Cl), have attracted 2 interest for optoelectronic applications such as highly efficient thin-film light-emitting diodes or wide-gap absorber materials for photovoltaics. However, phase segregation and secondary phases in as-deposited thin films are still considered to be limiting factors for devices based on CsPbX3. Here, we report a correlative electron microscopy and spectroscopy approach for the identification of secondary phases and their distributions in Cs-Pb-Br thin films, deposited by solution-based and coevaporation methods on various substrates. We identified phases by their compositional, structural, and optoelectronic properties, using X-ray diffraction, spectroscopy and a variety of microscopy techniques. We found that the Cs-Pb-Br films contain ternary Cs4PbBr6 and CsPb2Br5 phases in addition to CsPbBr3, a finding consistent with calculations of formation enthalpies by means of density functional theory showing that these values are very similar for the three ternary phases. We find that these phases can exhibit different spatial distributions inside the film and discuss the influence of the deposition method and synthesis parameters on the resulting phase composition of the Cs-Pb-Br layers.

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Section: Structural Properties Of Binary and Ternary Compounds In Thementioning

confidence: 90%

Spatial Phase Distributions in Solution-Based and Evaporated Cs–Pb–Br Thin Films

Caicedo‐Dávila

Funk

Lovrinčić³

et al. 2019

J. Phys. Chem. C

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“…David (1983) demonstrates that the propagation and displacement directions of the pure shear soft acoustic modes are coincident ferroelastic domain walls, which are mutually perpendicular to each other and may behave like "liquid" at the transition temperature. The elastic moduli C 11 -C~ 2, which represent the shear component for propogation direction of (110) and polarization plane of [-110], may go soft with ~-25~x+Y soft phonon mode; while the elastic modulus C66 , which represents the shear component for propogation direction of (100) and polarization plane of [010], may go soft with M~ soft phonon mode, in case of the ferroelastic phase transition in NaMgF 3 perovskite (Fleury et al 1974;Rousseau et al 1975;Hirotsu et al 1977). Future study ofNaMgF 3 perovskite with Brillouin scattering spectroscopy at high temperatures is needed to measure the elastic soft modes.…”

Section: Discussionmentioning

confidence: 99%

The single crystal elastic moduli of neighborite

Zhao

Weidner

1993

Phys Chem Minerals

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Abstract.The adiabatic elastic moduli of a single crystal of Neighborite (NaMgF3 perovskite) have been measured at ambient conditions using Brillouin spectroscopy. The adiabatic aggregate (Voight-Reuss-I-Iill) bulk modulus is K=75.6 GPa, and shear modulus is /~=46.7 GPa. The experimental results show the ratio of linear compressibilities/~h//~ = 0.80 for neighborite. These ratios reflect the different amounts of tilting freedom of the octahedral framework along each lattice axis of the perovskite structure. It is understood that the elastic compliance Sij of the crystal can directly sense the behavior of the octahedral tilting in the structural distortion of NaMgF 3 perovskite. The octahedral tilting angles are considered to be the order parameters of the ferroelastic phase transition in the perovskite structure. Single crystal elasticity data provide a basis for understanding the role of octahedral tilting in the ferroelasticity of perovskite. Together with high pressure compressional data, one can thus elucidate the relationship between crystal structure and physical properties of perovskite. A detailed assessment indicates that the dominant compression mechanism for NaMgF3 perovskite is shortening of the octahedral [Mg-F l bond, which is also true for orthorhombically distorted MgSiO3 perovskite.

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“…28) The energy had been submitted to analyze the elastic anomalies in successive phase transitions of the perovskite CsPbBr 3 caused by condensations of the M z 3 and R xy 25 mode. The M 3 mode and the antiferroelectric mode of PbZrO 3 lie on the same AE 3 transverse branch if we use an extended zone expression.…”

Section: Topology Of Order-parameter Vector Space and Cou-mentioning

confidence: 99%

Crystal Structure and Order Parameters in the Phase Transition of Antiferroelectric PbZrO₃

et al. 2003

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X-ray and neutron diffraction and dielectric measurements were performed for the antiferroelectric phase of PbZrO 3 . The antiferroelectric AE 3 (TO) and the R 25 superlattice-reflection intensities, and the pseudo-tetragonal lattice distortion of the perovskite sublattice showed the same temperature dependence below room temperature, showing a saturation below about 60 K. Above room temperature, however, they showed rather different temperature dependences. These temperature dependences can be well described by the free energy based on a group theoretical method, which includes a quantum effect. The atomic shifts do not necessarily conform to a simple concept of order parameter in soft mode condensation. However the antiferroelectric phase transition can be understood by the phenomenological theory for coupled order parameters if applied over the whole temperature region.

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Ultrasonic Velocity around the Successive Phase Transition Points of CsPbBr₃

Cited by 40 publications

References 13 publications

Spatial Phase Distributions in Solution-Based and Evaporated Cs–Pb–Br Thin Films

Spatial Phase Distributions in Solution-Based and Evaporated Cs–Pb–Br Thin Films

The single crystal elastic moduli of neighborite

Crystal Structure and Order Parameters in the Phase Transition of Antiferroelectric PbZrO₃

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Ultrasonic Velocity around the Successive Phase Transition Points of CsPbBr3

Cited by 40 publications

References 13 publications

Spatial Phase Distributions in Solution-Based and Evaporated Cs–Pb–Br Thin Films

Spatial Phase Distributions in Solution-Based and Evaporated Cs–Pb–Br Thin Films

The single crystal elastic moduli of neighborite

Crystal Structure and Order Parameters in the Phase Transition of Antiferroelectric PbZrO3

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Product

Resources

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Ultrasonic Velocity around the Successive Phase Transition Points of CsPbBr₃

Crystal Structure and Order Parameters in the Phase Transition of Antiferroelectric PbZrO₃