| NSF Org: |
CHE Division Of Chemistry |
| Recipient: |
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| Initial Amendment Date: | August 6, 2018 |
| Latest Amendment Date: | August 6, 2018 |
| Award Number: | 1802274 |
| Award Instrument: | Standard Grant |
| Program Manager: |
George Janini
CHE Division Of Chemistry MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | August 1, 2018 |
| End Date: | July 31, 2021 (Estimated) |
| Total Intended Award Amount: | $450,000.00 |
| Total Awarded Amount to Date: | $450,000.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
5801 S ELLIS AVE CHICAGO IL US 60637-5418 (773)702-8669 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
929 E 57th Street Chicago IL US 60637-1478 |
| 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): | Macromolec/Supramolec/Nano |
| 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
Professor Luping Yu of the University of Chicago is supported by the Macromolecular, Supramolecular and Nanochemistry (MSN) Program of the Division of Chemistry to develop synthetic approaches to prepare new electron donor-acceptor molecular building blocks and link them together in small chains termed oligomers. The oligomers have the shape of a ladder. The ladder oligomers are investigated to determine the relationship between molecular structure and function as electric charge transporters. The objective is to develop oligomers with enhanced emission of electrons as a result of absorption of light. The project integrates synthetic chemistry, material science, theoretical computation and device generation. The ultimate goal is to establish the foundation upon which useful organic materials are developed for potential applications in organic light emitting transistor (OLETs) and other molecular electronic devices. The intellectual properties developed during the course of conducting the project is commercialized by industrial partners. Another goal of this project is to nurture the next generation of scientists in materials chemistry and electronic device generation. Students and other professionals receive interdisciplinary training and learn the skills necessary to face future scientific challenges. Underrepresented minority students are involved in the project and encouraged to pursue scientific careers.
Conjugated ladder oligomers are a class of important materials that exhibit interesting optical and electrical properties. In this project, synthetic approaches involving several annulation reactions to ladder oligomers containing new electronic donor-acceptor (D-A) building motifs are developed. New concepts with emphasis on improved solubility and improved optoelectronic properties are formulated and a new generation of D-A ladder oligomers with unique charge transport properties are explored. Theoretical calculations are employed to inform the synthetic effort. These oligomers represent a new classis of organic semiconductors with controlled band gap, orbital energy levels and crystal structures. The electrical and optical properties of these materials and the relationship between molecular structure/crystal structure and charge transport property (mobility) are investigated. The aim is to prepare ladder oligomers with enhanced photoemission efficiency for applications in organic light emitting transistor (OLETs) and other electronic devices.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
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.
NSF Final outcomes report:
In the past three years, we have accomplished our proposed goals and beyond although the pandemic imposed challenge. The following is the summary of our accomplishments.
- Synthetic strategy towards new ladder systems and highly luminescent semi-ladder polymers have been developed. The Pd mediated cyclization reaction yielded ladder type of monomers with high photoluminescent efficiency. Total 18 polymers were synthesized.
- These polymers were found to be interesting candidate materials for organic light-emitting transistor (OLET).
- Studies on structure/property relationship indicated that energy level, emission color and intermolecular aggregation of polymers are influenced by subtle variation in the chemical structure. Among these 18 polymers, they can be calssified into three catagories. High photoluminescence quantum yields (PLQY) was obtained in three polymers: TPTI-CC, TPTI-C, and TPTI-F. Solution-processed tri-layered OLET devices were fabricated, which exhibited strong electroluminescence, balanced charge mobility, and external quantum yield (EQE) of 2.8%.
- Another class of polymer is those containing fluorene as comonomer. It was found that enhanced planarity, high crystalline, and a delicate balance in interchain aggregation contributed to high ambipolar charge mobilities and photoluminescent quantum yield. A new polymer named TPTQ-F showed excellent performances in solution-processed multi-layered OLET devices with an external quantum efficiency of 5.3%. We also found that fine-tuning in pi-pi interaction distance leads to optimization of LET properties, which can be attributed to the control of excimer formation.
- It was found that the cross conjugated semi-ladder copolymers, named as TPTQF-C and TPTQ-C, self-assemble into coiled foldamers with intramolecular H-aggregation, which can simultaneously retain high photoluminescent quantum yield and excellent charge transport. This unique aggregated structure led towards an impressive external quantum efficiency (EQE) of 6.9% and electroluminescent intensity of 2332 nW in solution-processed multi-layer OLET devices.
- Succeeded in recruiting minority undergraduate student (1) at the first 1.5 year, which was interrupted by pandemic.
- The project offered excellent opportunities for postdoctoral training (2). One of them assumed academic position as assistant Professor.
- 11 Research Articles published under support of this grant.
- Three Ph.D. theses defended by graduate students working on this grant., all of them secured an industrial job.
Last Modified: 08/12/2021
Modified by: Luping Yu
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