Ab initio study of nonlinear and vibrationally-controlled optoelectronic responses in semiconductors
type: CreativeWork
description: Optoelectronic materials are an important driver of many modern technologies. These materials couple their interaction with light to their electronic properties in a range of—often tunable—ways. Responses such as generation of photocurrent from incident light or generation of light by electro- or photoluminescence are vital to many existing and emerging applications. Other more complex linear and nonlinear properties offer unique avenues for optical control. In this dissertation, we will explore a particular class of optical response, where DC photocurrent is generated in a homogeneous material without an interface. This bulk photovoltaic effect (BPVE) shows promise for sensing applications, characterization of quantum materials, and higher efficiency power conversion, but some aspects remain poorly understood. We first outline a materials design strategy to predict distortions that will have a significant impact on the BPVE and use this method to better understand the photoresponse of monolayer MoS2. Then, we discuss two potential mechanisms that could contribute to the BPVE. While these mechanisms have been discussed in model systems, it is difficult to determine their relevance in real materials. We outline new methods for calculating the current contribution due to electron-phonon scattering that occurs during light excitation, and we estimate another current that arises during carrier recombination. From first-principles calculations, we predict the contribution of these mechanisms to the BPVE in several prototypical materials. Then, we turn our attention to hybrid organic-inorganic perovskites, which are a class of materials well known for their excellent optoelectronic performance. The presence of organic components in these materials lends a high degree of tunability and leads to complex dynamical behavior. We use first principles study to better understand hybrid perovskites. We model the thermodynamic, electronic, and optical properties of a perovskite in …
abstract: Optoelectronic materials are an important driver of many modern technologies. These materials couple their interaction with light to their electronic properties in a range of—often tunable—ways. Responses such as generation of photocurrent from incident light or generation of light by electro- or photoluminescence are vital to many existing and emerging applications. Other more complex linear and nonlinear properties offer unique avenues for optical control. In this dissertation, we will explore a particular class of optical response, where DC photocurrent is generated in a homogeneous material without an interface. This bulk photovoltaic effect (BPVE) shows promise for sensing applications, characterization of quantum materials, and higher efficiency power conversion, but some aspects remain poorly understood. We first outline a materials design strategy to predict distortions that will have a significant impact on the BPVE and use this method to better understand the photoresponse of monolayer MoS2. Then, we discuss two potential mechanisms that could contribute to the BPVE. While these mechanisms have been discussed in model systems, it is difficult to determine their relevance in real materials. We outline new methods for calculating the current contribution due to electron-phonon scattering that occurs during light excitation, and we estimate another current that arises during carrier recombination. From first-principles calculations, we predict the contribution of these mechanisms to the BPVE in several prototypical materials. Then, we turn our attention to hybrid organic-inorganic perovskites, which are a class of materials well known for their excellent optoelectronic performance. The presence of organic components in these materials lends a high degree of tunability and leads to complex dynamical behavior. We use first principles study to better understand hybrid perovskites. We model the thermodynamic, electronic, and optical properties of a perovskite in …
author: Schankler, Aaron, Matthew
language: en
keywords: Chemistry, Physics
date published: 2024
date modified: 2026-07-24T03:45:49Z
provider: University of Pennsylvania
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Pennsylvania