Committee Members:

Prof. Natalie Stingelin, Advisor, MSE/ChBE

Prof. Carlos Silva-Acuña, Advisor, MSE/CHEM/PHYS

Prof. Juan Pablo Correa-Baena, MSE

Prof. Joshua Kretchmer, CHEM

Prof. Phillip First, PHYS

Prof. Vinod Menon, The City University of New York

Prof. Eric Bittner, University of Houston

Light-matter coupling in organic and hybrid organic/inorganic semiconductors

Abstract:

Controlling light-matter coupling has attracted plenty of scientific interest since it can lead to photon-based computing and new chemical reaction pathways, opening doors for quantum information technologies and novel chemistry. Light-matter coupling occurs when excitonic transitions of a semiconductor, placed within an optical microcavity, couple with optical modes, i.e., standing electromagnetic waves in the microcavity structure. Weak coupling in these systems can lead to photon quantum phases, while strong coupling leads to emergent hybrid light-matter exciton-polariton states that also display quantum phenomena. Both, photon quantum phases and polariton states represent pathways to modify the properties of light (e.g., spatial and time coherence) and matter (e.g., molecular dynamics and photophysical processes).

This Ph.D. proposal focuses on how to attain photon quantum phases and exciton-polaritons in organic and hybrid organic/inorganic semiconductors (e.g., organic dyes and Ruddlesden-Popper metal halide perovskites) to ultimately modify light and matter properties. The first aim of my research is to design and fabricate fully solution-processed microcavities that exhibit the formation of photon quantum phases and strong light-matter coupling in a target semiconductor. The monolithically solution-processed microcavity structures proposed here comprise alternating layers of a high-refractive-index titanium oxide hydrate/poly(vinyl alcohol) molecular hybrid and a low-refractive-index commodity polymer. These solution-processed microcavities represent a simple alternative to inorganic microcavities and are also expected to be more compatible with temperature-sensitive materials. Second, we will describe the photophysical processes involved in light-matter coupling in organic and hybrid organic/inorganic semiconductors to deliver a mechanistic understanding of the population and thermalization of photon quantum phases and exciton-polaritons in these material classes. For this purpose, we will employ diverse spectroscopic techniques including k-space microscopy, transient reflectivity and absorption, excitation correlation spectroscopy, and two-dimensional coherent spectroscopy. Last, we will tune photophysical processes involved in light-matter coupling through microcavity design and assess a series of structures for controlling molecular bistable states via light-matter coupling. The overall purpose of this thesis is to reliably attain light-matter coupling in organic and hybrid organic/inorganic semiconductors and to deliver a detailed understanding of their photophysics for moving toward their utilization in chemistry and quantum information applications.