Phase segregation in mixed-halide perovskites affects charge-carrier dynamics while preserving mobility.

ABSTRACT: Mixed halide perovskites can provide optimal bandgaps for tandem solar cells which are key to improved cost-efficiencies, but can still suffer from detrimental illumination-induced phase segregation. Here we employ optical-pump terahertz-probe spectroscopy to investigate the impact of halide segregation on the charge-carrier dynamics and transport properties of mixed halide perovskite films. We reveal that, surprisingly, halide segregation results in negligible impact to the THz charge-carrier mobilities, and that charge carriers within the I-rich phase are not strongly localised. We further demonstrate enhanced lattice anharmonicity in the segregated I-rich domains, which is likely to support ionic migration. These phonon anharmonicity effects also serve as evidence of a remarkably fast,

SUBMITTER: Motti SG 

PROVIDER: S-EPMC8630172 | biostudies-literature | 2021 Nov

REPOSITORIES: biostudies-literature