Date of Award

8-2022

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Physics and Astronomy

Committee Chair/Advisor

Apparao. M. Rao

Committee Member

Murray Daw

Committee Member

Chad Sosolik

Committee Member

Lin Zhu

Committee Member

Sriparna Bhattacharya

Abstract

Perovskites are a novel class of materials that have piqued the interest of researchers in photovoltaics, photodetectors, and optoelectronics. In this study, we measure and elucidate in situ ultrafast carrier dynamics in both organic and inorganic, lead, and non-lead-based halide perovskite thin films using ultrafast photocurrent spectroscopy (UPCS) with a sub-25 ps time resolution. The UPCS technique enables us to define carrier transport dynamics in spatial, temporal, and energy landscapes via measurements at different electric fields, laser intensities, and temperatures. Here we explore and analyze solution-processed bulk MAPbI3 and nanocrystalline CsPbI3-based devices and novel non-lead double-layered perovskite devices through UPCS. In particular, we elucidate carrier transport dynamics focusing on early-time phonon interactions and the role played by the material defects. From our data and analysis, we successfully elucidated the role of ultra-shallow trap levels in MAPbI3 for the first time, while in nanocrystalline CsPbI3, we identified the optical phonon responsible for carrier phonon scattering through the analysis of the transport index number. Regarding double-layered perovskites, spectroscopic analysis of their charge carrier dynamics revealed the feasibility of using them in future optoelectronic applications. The design of lead-free, environmentally friendly perovskites can potentially replace current lead-based materials.

Author ORCID Identifier

0000-0002-3414-741X

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