The phase diagram of a mixed halide (Br, I) hybrid perovskite obtained by synchrotron X-ray diffraction

Abstract

The phase diagram elucidates structural changes and phase separation effects, induced by halide substitution in hybrid perovskite MAPb(I,Br)3 solid solution.

Investigating the Tetragonal‐to‐Orthorhombic Phase Transition of Methylammonium Lead Iodide Single Crystals by Detailed Photoluminescence Analysis

“…[ 48 ] With the assumption that lattice dilation is the dominant factor for the temperature‐dependent shift of the PL maximum, [ 6,12 ] we find tensile strain values of 85–165 MPa (see Section S7 in the Supporting Information for details). However, recent studies demonstrated that the unit cell volume of the orthorhombic phase is smaller than the one of the tetragonal phase, [ 4,45,49,50 ] and thus there should be compressive strain instead of tensile strain to affect the tetragonal inclusions. Room temperature measurements showed that pressure on MAPbI 3 leads to a red shift.…”

Photoinduced Anion Segregation in Mixed Halide Perovskites

“…Apparent are structural dependencies on halide and A + composition. MAPbI 3 ( Figure IA) adopts a β-phase at 300 K and transitions to its α-phase at~330 K. MAPbBr 3 prefers its α-phase above~250 K ( Figure IB) [74]. FAPbI 3 ( Figure IC) assumes its α-phase above~440 K but prefers its non-perovskite δ hex -phase at~300 K [13].…”

Temperature-Dependent Optical Band Gap in CsPbBr3, MAPbBr3, and FAPbBr3 Single Crystals

“…The upper bound of the temperature window for the tetragonal phase is only 20 K before the lattice becomes cubic, and such an interval is too narrow to extract accurate fitting parameters considering that intermediate phases might exist. 54 However, for the sake of completeness, we added the expected transition point from literature data at 403 K. 20 …”