Elastic Constants, Optical Phonons, and Molecular Relaxations in the High Temperature Plastic Phase of the CH3NH3PbBr3 Hybrid Perovskite | Zendy

A. Létoublon | Zendy; Serge Paofai | Zendy; Benoît Rufflé | Zendy; P. Bourges | Zendy; Bernard Hehlen | Zendy; Thierry Michel | Zendy; C. Écolivet | Zendy; Olivier Durand | Zendy; Stéphane Cordier | Zendy; Claudine Katan | Zendy; Jacky Even | Zendy

Open Access

Elastic Constants, Optical Phonons, and Molecular Relaxations in the High Temperature Plastic Phase of the CH₃NH₃PbBr₃ Hybrid Perovskite

Author(s) -

A. Létoublon,

Serge Paofai,

Benoît Rufflé,

P. Bourges,

Bernard Hehlen,

Thierry Michel,

C. Écolivet,

Olivier Durand,

Stéphane Cordier,

Claudine Katan,

Jacky Even

Publication year - 2016

Publication title -

the journal of physical chemistry letters

Language(s) - English

Resource type - Journals

ISSN - 1948-7185

DOI - 10.1021/acs.jpclett.6b01709

Subject(s) - brillouin spectroscopy , phonon , perovskite (structure) , plastic crystal , inelastic neutron scattering , condensed matter physics , tetragonal crystal system , raman spectroscopy , phase (matter) , brillouin scattering , brillouin zone , resonant ultrasound spectroscopy , relaxation (psychology) , materials science , crystal (programming language) , phase transition , chemistry , neutron scattering , crystallography , optics , scattering , laser , physics , elastic modulus , computer science , composite material , psychology , social psychology , programming language , organic chemistry

Low frequency dynamics has been studied in a CH 3 NH 3 PbBr 3 hybrid perovskite single crystal by using four different spectroscopy techniques: coherent inelastic neutron, Raman and Brillouin scatterings, and ultrasound measurements. Sound velocities were measured over five decades in energy to yield the complete set of elastic constants in a hybrid halide perovskite crystal in the pseudocubic plastic phase. The C 44 shear elastic constant is very small, leading to a particularly low resistance to shear stress. Brillouin scattering has been used to study the relaxation dynamics of methylammonium cations and to evidence translation-rotation coupling associated with the cubic to tetragonal phase transition at T c ≈ 230 K. Low frequency and highly damped optical phonons observed using both Raman and inelastic neutron below 18 meV, do not present softening close to T c . The critical dynamics at T c ≈ 230 K is compatible with an order-disorder character, dominated by relaxational motions of the molecules.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.

Having issues? You can contact us here

Accelerating Research