AmericanChemicalSociety.com

With the no-cost extension of my PRF grant underway this year my group of undergraduate students and I have achieved substantial success illustrated by a second published paper in the Journal of Physical Chemistry, an oral presentation at the 238^th National ACS meeting and an upcoming poster presentation at the 2009 MRS Fall meeting in Boston. The work presented in each case is directly associated with this funded project. Another two peer-reviewed papers are expected, with one in preparation. My group’s work continues to attract strong students due in large part to my expectations for our communication of results, and productivity abounds. I manage my students more through a senior-to-freshman hierarchical approach and students flourish with the opportunity to guide more inexperienced members as they start to see the big picture of our research. I continue to use self-evaluation tools to better organize group targets and personnel.

Receipt of this grant allows me to emphasize RIT as a top-tier undergraduate research institution. My personal ambition and career goals have been raised. I submitted an NSF CAREER grant proposal that accounts for the next five years of my academic life and results obtained from the PRF grant were critical for my continuing progress in the newly proposed work. I currently see greater stability and positional strength within my own institute, recently taking on group leadership of a polymer photovoltaic research initiative at RIT’s NanoPower Research Laboratory (NPRL).

I have six active students working on projects linked to my proposal. They learn the importance of critical thinking, reproducibility and accuracy. I provide them with the tools to be excellent scholars and effective problem solvers. I strongly encourage further education beyond their undergraduate studies and expect strong careers for them in the sciences. Four recent students who have worked on this research are actively seeking graduate education in 2009-10; Filip Ambrosio continues to take advanced science classes to strengthen his application for dental school, RIT Pasto Award Winner Susan Spencer and Amanda Preske add to glowing undergraduate track records by continuing their summer research to present in Boston at the MRS national meeting in December, and Jessica Alexander attained recognition nationally as a 2009 Goldwater Scholar, and locally through the ACS Rochester Section 2009 Pricilla Carney Jones Scholarship.

Our ongoing work can be broken down as follows:

1. Single-Wall Carbon Nanotubes (SWCNT) and their interactions with a library of molecular fluorophores.

This work came about after follow-up on the unusual results of a control experiment, documented in my original ACS-PRF grant proposal. We continue to investigate the interaction of SWCNT with derivatives of well-known molecular fluorphores so as to better understand the non-covalent surface interactions of carbon nanotubes as a function of nanotube size and potentially chirality. Further work with this probe allows us to expand our understanding of interactions between SWCNT and the solvents used to disperse them. 

2. Physical and electronic interactions of SWCNT with substituted phenylene-vinylene conjugated polymers (MEH-PPV).

We continue to study the interactions of MEH-PPV and CoMoCat SWNT using absorbance and fluorescence techniques. Fluorescence quenching data indicates that the equilibrium constant governing surface coverage of SWCNTs is dependent upon the solvent, the chemical nature of the polymer and also the concentration of the polymer.

In summary, our work continues to provide strong contributions to the further understanding of interactions between SWNT and the functional groups of organic materials ranging in size. Regarding the fluorescence quenching of conjugated polymers by these nanotubes, we look to prove our model of physical interaction and the associated quenching mechanism with a full complement of experimental data. We intend to assess the mechanism’s universal application and consider its impact upon photovoltaic efficiency in a polymer bulk heterojunction device. In truth, excited state quenching may lead to loss of performance but, on the other hand, quenching through electron transfer may demonstrate the potential of carbon nanotubes in increasing solar cell efficiencies.