13-19 June 2015
University of Alberta
America/Edmonton timezone
Welcome to the 2015 CAP Congress! / Bienvenue au congrès de l'ACP 2015!

Ultrafast dynamics of mobile charges and excitons in hybrid lead halide perovskites

16 Jun 2015, 08:45
30m
CCIS L2-200 (University of Alberta)

CCIS L2-200

University of Alberta

Invited Speaker / Conférencier invité Division of Atomic, Molecular and Optical Physics, Canada / Division de la physique atomique, moléculaire et photonique, Canada (DAMOPC-DPAMPC) T1-10 THz science and applications (DAMOPC) / Sciences et applications des THz (DPAMPC)

Speaker

David Cooke (McGill University)

Description

In this talk we discuss recent experiments using ultra-broadband time-resolved THz spectroscopy (uTRTS) studying charge and excitonic degrees of freedom in the novel photovoltaic material CH3NH3PbI3. This technique uses near single-cycle and phase stable bursts of light with an ultra-broad bandwidth spanning 1 - 125 meV to take snapshots of a material's dielectric function or optical conductivity on femtosecond time scales after photoexcitation. These transient spectra reveal free charge transport properties on unprecedented time scales, and at the same time can probe internal excitations of Coulombically bound excitons. It is therefore an ideal technique for studying materials related to solar energy conversion such as semiconducting polymers, quantum dots and even the new hybrid metal halide perovskites. We apply uTRTS to a single crystal of CH3NH3PbI3, temporally resolving the charge carrier generation dynamics, the screening of infrared active phonons and the dissociation of excitons. Our measurements reveal remarkably high charge carrier mobilities on ultrafast time scales, as well as the importance of screening at elevated carrier densities.

Primary author

David Cooke (McGill University)

Co-authors

Arkady Yartsev (Lund University) Carlito Ponseca Jr. (Lund University) Costantinos Stoumpos (Northwestern University) David Valverde-Chavez (McGill University) Mercouri Kanatzidis (Northwestern University) Villy Sundstrom (Lund University)

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