| NSF Org: |
CHE Division Of Chemistry |
| Recipient: |
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| Initial Amendment Date: | April 12, 2016 |
| Latest Amendment Date: | April 12, 2016 |
| Award Number: | 1565930 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Tingyu Li
tli@nsf.gov (703)292-4949 CHE Division Of Chemistry MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | July 1, 2016 |
| End Date: | June 30, 2020 (Estimated) |
| Total Intended Award Amount: | $435,000.00 |
| Total Awarded Amount to Date: | $435,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
1 UNIVERSITY OF NEW MEXICO ALBUQUERQUE NM US 87131-0001 (505)277-4186 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
Albuquerque NM US 87131-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | CMFP-Chem Mech Funct, and Prop |
| Primary Program Source: |
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| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
In this project funded by the Chemical Structure, Dynamics and Mechanism B Program of the Chemistry Division, Professor Martin L. Kirk of the Department of Chemistry and Chemical Biology at the University of New Mexico is studying how electronically active molecules can be used in molecular electronics and other molecule-based technologies. Prof. Kirk is studying (1) how electrons flow through the molecules and can be controlled, (2) how the structures of the molecules affect their absorption of light, and (3) the nature of the molecules' excited states after light has been absorbed. The research is interdisciplinary and positioned at the interface of organic, inorganic, and physical chemistry and is providing enhanced opportunities for the education and training of next generation scientists. Professor Kirk is involved in teaching, training and mentoring student researchers, including those from underrepresented groups. He is also participating in outreach projects in New Mexico including those associated with the Albuquerque Explora! Museum and NanoDays.
The project goals focus on using creatively designed magnetic exchange coupled Donor-Bridge-Acceptor biradical systems to explore (1) molecular quantum interference and molecular rectification, (2) anisotropic covalency induced spin orbit coupling contributions to excited state lifetimes, and (3) how excited state magnetic exchange interactions affect magneto-optical activity, spin polarization, and excited state relaxation pathways. The project utilizes a combined spectroscopic approach augmented by theory and computations to address these problems. Regarding molecular electron transport phenomena, Donor-Bridge-Acceptor electronic coupling in the context of molecular conductance is studied in order to test recent theoretical hypotheses and compare results to those that have been obtained under device conditions. This work could directly impact the molecular electronics field. Modulation of spin orbit coupling through anisotropic covalency impacts the ability to control relaxation rates and pathways in photoexcited states. Work using magnetic circular dichroism and transient spectroscopies reveals the nature of complex multi-spin excited state magnetic exchange interactions that derive from photoexcitation. The research contributes to a greater understanding of excited state magnetism, exciton-polaron coupling, and solar energy conversion. The project advances knowledge and understanding in the field of donor-acceptor interactions and contribute substantially to the understanding of molecular electronics, atom level control of excited state lifetimes, and spin effects on excited state processes.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
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PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
This project focused on using Donor-Acceptor molecules to provide deep insight into (1) how electronic structure influences current flow through a molecule for applications in molecular electronics, and (2) the control of molecular excited state processes using the quantum mechanical concepts of spin and spin-orbit coupling. Collectively, the outcomes of this project impact the development of molecular and molecule-based technologies at the nanoscale.
During the execution of this project, we determined important ground and excited state electronic structure contributions to molecular electron transport mediated by asymmetric bridge molecules and bridge molecules that possess unpaired spin. This has contributed to a greater understanding of how specific molecular conduits affect donor-acceptor electronic coupling and current rectification, both of which are expected to further the development of the molecular electronics field. Another project outcome highlights the utility of measuring a specific ground state property (e.g. NMR chemical shifts, magnetic exchange interactions) and using this information to predict the lifetimes of excited states generated by photoexcitation. This suggests a path forward to dramatically impact the molecular photophysics and photochemistry fields by designing new molecules with very specific excited state lifetimes. We were also able to show that multi-spin excited state exchange interactions in our donor-acceptor systems can produce dramatic changes in spin polarization between excited states of the same spin multiplicity. This effect may allow for encoded information to be stored transiently in molecular excited and ground states, and be read using spectroscopic techniques for quantum information science applications.
Our research efforts aimed at developing a greater understanding of molecular electronics, spintronics, and excited state processes were performed by a combination of undergraduate, graduate, and postdoctoral researchers as part of a collaborative interdisciplinary team. Researchers on the project gained invaluable experience in organic and inorganic synthesis, the implementation of advanced multicomponent spectroscopic techniques, and the utilization of state-of-the-art computational approaches to the development of electronic structure descriptions of molecular electron transport, excited state lifetime modulation, and excited state spin polarization effects.
Broader components of the research outcomes will enhance our understanding of electron transport/transfer phenomena in materials science and biology, and our understanding of photovoltaic cells, LEDs, non-radiative decay processes, information encoding, and new design constructs for quantum information processing. We have advanced discovery and understanding while promoting teaching, training, and learning through student research presentations at meetings and by incorporating both undergraduate and high school students directly in our research projects. Broader participation has been encouraged and advanced by a research team that has traditionally relied on critical contributions from underrepresented groups.
Last Modified: 10/27/2020
Modified by: Martin L Kirk
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