2020 Theses Doctoral

Dynamics of Light-Matter Coupling in Lead Halide Perovskites

Schlaus, Andrew

Lead halide perovskites are attractive material systems for both classical and quantum light emission because of their facile and diverse synthetic techniques, broad tunability in bandgap energy, high emission quantum efficiencies, and the possibility strong light-matter coupling. Despite extensive research into lead halide perovskites, there remain extensive debates into the mechanisms behind various light emission processes. This thesis has three objectives. First, to understand the properties of perovskite nanowire lasers as well as the underlying photophysics. Second, to differentiate between behavior in the weak versus strong light matter coupling regimes. Finally, to understand where perovskites in distributed Bragg reflector microcavities fall in these regimes. A combination of static, time, and angle resolved spectroscopy is used to study nanowire and microcavity systems in combination with numerical methods to interpret the results. Perovskite nanowire emission is shown to arise from stimulated emission from an electron-hole plasma and coupling with bulk plasmons, while perovskite microcavities offer the possibility of strong coupling and emission from a polariton condensate. The spatial confinement of the photonic structure and quasi-spin orbit coupling in perovskite cavities are discussed as powerful tools which could extend the coherence time of polariton condensates in these systems.