| NSF Org: |
CHE Division Of Chemistry |
| Recipient: |
|
| Initial Amendment Date: | June 26, 2019 |
| Latest Amendment Date: | June 26, 2019 |
| Award Number: | 1905179 |
| Award Instrument: | Standard Grant |
| Program Manager: |
John Papanikolas
jpapanik@nsf.gov (703)292-8173 CHE Division Of Chemistry MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | August 1, 2019 |
| End Date: | July 31, 2023 (Estimated) |
| Total Intended Award Amount: | $185,000.00 |
| Total Awarded Amount to Date: | $185,000.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
601 S HOWES ST FORT COLLINS CO US 80521-2807 (970)491-6355 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
200 West Lake Street Fort Collins CO US 80521-4593 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Macromolec/Supramolec/Nano |
| Primary Program Source: |
|
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
Metal nanoparticles can be just a few nanometers in size and contain just tens to hundreds of metal atoms. When the nanoparticles are isolated from one another, exposure to light typically results in heating of the particle, which then dissipates energy into the surrounding solvent. However, connect two particles together and that light absorption can be converted into a bright luminescence. With support from the Macromolecular, Supramolecular and Nanochemistry Program in the Division of Chemistry, Professors Christopher Ackerson (Colorado State University), Christine Aikens (Kansas State University), and Kenneth Knappenberger (Pennsylvania State University) are working to understand the mechanism of this light emission. The team combines precision nanoparticle synthesis and characterization with cutting-edge theoretical calculations and experimental spectroscopy to determine the unique luminescence properties of these systems. Their discoveries could improve bioimaging and impact emerging quantum information technologies. The project also provides a unique multi-disciplinary environment for student training, and outreach activities to K-12 students are introducing underrepresented students to scientific research.
The primary thrusts of this proposal are to determine how ligand substitution affects the geometric and electronic structure of quantum-confined gold nanoclusters (AuNCs) and their assemblies, and to understand the influence of these properties on electronic relaxation dynamics and photoluminescence yields. The team is also developing an understanding of how the properties of AuNC monomers impact electronically coupled dimers and extended structures. The proposed research features structurally precise monolayer-protected gold clusters and progresses to include n-glyme-bridged multimers. The specific objectives include: 1) to determine the compatible ligands for which glyme molecules can be incorporated into the AuNC passivation shell, and to understand the range of clusters that can be assembled using glyme-driven chemistry; 2) to describe the nature of the interaction -- both electronically and geometrically -- of glyme with AuNC monomers and larger assemblies; and 3) to describe how the properties described in 1 and 2 affect state-resolved carrier dynamics of AuNC monomers, inter-cluster electronic coupling and transfer, and photoluminescence emission. These goals are being achieved by combining colloidal AuNC synthesis and purification, computational-based predictions, and experimental electron dynamics research. The proposed efforts include plans to provide student education at the graduate and undergraduate levels in three pillars of nanoscience.
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
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
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.
Under the award, "Collaborative Research: Collaborative Research: Electronic and Geometric Structure of n-Glyme Assembled Metal Clusters," the Ackerson lab at Colorado State University collaborated with the Knappenberger Lab of Pennsylvania State University and the Aikens Lab of Kansas State University. In the overall collaborative award, the goal was to "make, measure and model" how molecules that bind weakly to clusters of gold atoms can co-exist with molecules that bind strongly to gold clusters – on the same cluster. The weak-binding molecules were observed to facilitate the assembly of gold clusters, where the assemblies had emergent optical and possibly geometric properties.
At less than one billionth of a meter in diameter, these discrete collections of atoms, or "nanoclusters" may be ultimately useful in solar-to-electric energy conversion devices, optical sensors, and medical diagnostics and therapeutics, among others. However, many of these proposed applications require understanding of the electronic and geometric structures of such clusters.
The role of the Ackerson group in this award was to synthesize or make the nanoclusters that were being measured in cutting edge ways by the Knappenberger group and theoretically modeled by the Aikens group. In this award, the Ackerson lab produced samples of nanoclusters that were subsequently measured in the Knappenberger lab. Many of these samples came from known synthetic proceedures. The role of the Ackerson lab was also to develop novel syntheses of gold clusters that contained weak-binding ligands and their assemblies so that the properties of such clusters could be measured and modeled.
As a result of this award, we developed new synthetic routes for gold clusters that include weak ligands (such as glymes). We found routes to making water-soluble and organo-soluble gold clusters that include exactly one weakly bound ligand. Such clusters may be useful in biological-labeling experiments. We worked with Prof Aikens to develop structural models for how the weak-binding ligands could structurally bind to the gold cluster. We also determined empirical ligand structures on some gold clusters. Those structures enabled a comprehensive analysis of bond-rotations on ligand protected gold clusters, highlighting that only some bond-angles are observed. We also provided samples of gold clusters to Prof Knappenberger’s team, which were then measured spectroscopically.
The results of these research findings were reported in several peer-reviewed papers, published in journals under the American Chemical Society family of journals and the Royal Society of Chemistry family of journals.
In addition to the research findings, this grant was supported the training of several Chemistry PhD students, as well as several undergraduate students with majors in Chemistry and Biochemistry.
Last Modified: 12/27/2023
Modified by: Christopher Ackerson
Please report errors in award information by writing to: awardsearch@nsf.gov.
