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Fundamental Charge Transfer Dynamics in Two-Dimensional Transition Metal Dichalcogenide Heterostructures
Fundamental Charge Transfer Dynamics in Two-Dimensional Transition Metal Dichalcogenide Heterostructures
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20250211151132
- ISBN
- 9798382718941
- DDC
- 540
- 저자명
- Myers, Alexis R.
- 서명/저자
- Fundamental Charge Transfer Dynamics in Two-Dimensional Transition Metal Dichalcogenide Heterostructures
- 발행사항
- [Sl] : University of Colorado at Boulder, 2024
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2024
- 형태사항
- 161 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 85-11, Section: B.
- 주기사항
- Advisor: Blackburn, Jeffrey;Rumbles, Garry.
- 학위논문주기
- Thesis (Ph.D.)--University of Colorado at Boulder, 2024.
- 초록/해제
- 요약Innovation in optoelectronic semiconductor devices is driven by a fundamental understanding of how to move charges and/or excitons (electron-hole pairs) in specified directions for making fuels and electricity. Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted increasing interest for energy harvesting and catalytic applications due to their diverse and tunable electronic and optical properties and high charge carrier mobilities, serving as good 2D quantum confined model systems. In this thesis, we explore design strategies and synthesis of monolayer TMDCs for use in TMDC based heterostructures (Chapter 2) and how the potential energy landscape at various TMDC based interfaces plays a crucial role in charge separation behavior.Two drawbacks for using TMDCs for e.g., photovoltaic or solar fuels applications is the relatively large exciton binding energies and short (tens of picoseconds) exciton recombination lifetimes. One strategy to overcome these drawbacks is the creation of heterojunctions that dissociate photogenerated excitons to produce long-lived charge separation across interfaces. Chapters 3 and 5 focus on creating mixed-dimensionality heterojunctions between TMDCs and organic semiconductors to achieve efficient and long-lived charge-separated states. Here we study charge transfer (CT) dynamics of TMDC interfaces with single-walled carbon nanotubes (SWCNTs) and small molecules, the energy level offsets suitable for charge and energy transfer (ET), as well as the impact of covalent bonding on SWCNT/organic interfaces for triplet acceptance and sensitization. Interfaces are characterized with a variety of steady-state and time resolved techniques and initial results show success in selective isolation of charge vs energy transfer pathways and increased carrier lifetimes, emphasizing well defined charge associated spectral features in transient absorption spectroscopy are key to the continued understanding of how to reliably quantify charge transfer quantum yield.In Chapter 4, we expand upon the work of Chapter 3, utilizing steady-state and transient absorption spectroscopy to correlate monolayer MoS2 electron density with the easily measured metric of excitonic optical absorption quenching in a variety of mixed-dimensionality s-SWCNT/MoS2 heterostructures. By employing a 2D phase-space filling model, the resulting correlation elucidates the relationship between charge density, local dielectric environment, and concomitant excitonic properties. Our findings provide well-constrained ranges for exciton mass and local dielectric constant that can be used by the community to estimate both ground- and excited-state carrier densities in a wide range of MoS2-based systems. Overall, demonstrating that the successful design and device integration of TMDC-based nanoscale heterointerfaces hinges upon precise manipulation of both ground- and excited-state charge carrier (electron and hole) densities.
- 일반주제명
- Chemistry
- 일반주제명
- Nanoscience
- 일반주제명
- Materials science
- 일반주제명
- Engineering
- 키워드
- Carbon nanotubes
- 키워드
- Charge transfer
- 키워드
- Excitons
- 키워드
- Heterojunctions
- 기타저자
- University of Colorado at Boulder Chemistry
- 기본자료저록
- Dissertations Abstracts International. 85-11B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520250211151132
■006m o d
■007cr#unu||||||||
■020 ▼a9798382718941
■035 ▼a(MiAaPQ)AAI31147744
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a540
■1001 ▼aMyers, Alexis R.▼0(orcid)0000-0002-6432-5758
■24510▼aFundamental Charge Transfer Dynamics in Two-Dimensional Transition Metal Dichalcogenide Heterostructures
■260 ▼a[Sl]▼bUniversity of Colorado at Boulder▼c2024
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2024
■300 ▼a161 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 85-11, Section: B.
■500 ▼aAdvisor: Blackburn, Jeffrey;Rumbles, Garry.
■5021 ▼aThesis (Ph.D.)--University of Colorado at Boulder, 2024.
■520 ▼aInnovation in optoelectronic semiconductor devices is driven by a fundamental understanding of how to move charges and/or excitons (electron-hole pairs) in specified directions for making fuels and electricity. Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted increasing interest for energy harvesting and catalytic applications due to their diverse and tunable electronic and optical properties and high charge carrier mobilities, serving as good 2D quantum confined model systems. In this thesis, we explore design strategies and synthesis of monolayer TMDCs for use in TMDC based heterostructures (Chapter 2) and how the potential energy landscape at various TMDC based interfaces plays a crucial role in charge separation behavior.Two drawbacks for using TMDCs for e.g., photovoltaic or solar fuels applications is the relatively large exciton binding energies and short (tens of picoseconds) exciton recombination lifetimes. One strategy to overcome these drawbacks is the creation of heterojunctions that dissociate photogenerated excitons to produce long-lived charge separation across interfaces. Chapters 3 and 5 focus on creating mixed-dimensionality heterojunctions between TMDCs and organic semiconductors to achieve efficient and long-lived charge-separated states. Here we study charge transfer (CT) dynamics of TMDC interfaces with single-walled carbon nanotubes (SWCNTs) and small molecules, the energy level offsets suitable for charge and energy transfer (ET), as well as the impact of covalent bonding on SWCNT/organic interfaces for triplet acceptance and sensitization. Interfaces are characterized with a variety of steady-state and time resolved techniques and initial results show success in selective isolation of charge vs energy transfer pathways and increased carrier lifetimes, emphasizing well defined charge associated spectral features in transient absorption spectroscopy are key to the continued understanding of how to reliably quantify charge transfer quantum yield.In Chapter 4, we expand upon the work of Chapter 3, utilizing steady-state and transient absorption spectroscopy to correlate monolayer MoS2 electron density with the easily measured metric of excitonic optical absorption quenching in a variety of mixed-dimensionality s-SWCNT/MoS2 heterostructures. By employing a 2D phase-space filling model, the resulting correlation elucidates the relationship between charge density, local dielectric environment, and concomitant excitonic properties. Our findings provide well-constrained ranges for exciton mass and local dielectric constant that can be used by the community to estimate both ground- and excited-state carrier densities in a wide range of MoS2-based systems. Overall, demonstrating that the successful design and device integration of TMDC-based nanoscale heterointerfaces hinges upon precise manipulation of both ground- and excited-state charge carrier (electron and hole) densities.
■590 ▼aSchool code: 0051.
■650 4▼aChemistry
■650 4▼aNanoscience
■650 4▼aMaterials science
■650 4▼aEngineering
■653 ▼aCarbon nanotubes
■653 ▼aCharge transfer
■653 ▼aExcitons
■653 ▼aHeterojunctions
■653 ▼aTransition metal dichalcogenides
■690 ▼a0485
■690 ▼a0794
■690 ▼a0565
■690 ▼a0537
■71020▼aUniversity of Colorado at Boulder▼bChemistry.
■7730 ▼tDissertations Abstracts International▼g85-11B.
■790 ▼a0051
■791 ▼aPh.D.
■792 ▼a2024
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17160892▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
