1. 2D-IR VIBRATIONAL ECHO SPECTROSCOPY OF CONDUCTING POLYMERS Audrey A. Eigner Prof. Aaron Massari University of Minnesota - Twin Cities Department of Chemistry n

2. Conducting Polymers Potential Applications: Electronics (Batteries, transistors, ICs, sensors, etc.) Opto-electronics (OLEDs, photovoltaics, lasers, xerography, etc.) Sony OLED TVs 2007 -Numerous studies have been directed towards understanding the relationship between charge transport in these polymers and their static molecular structures, but very little attention has been paid to the role of structural dynamics.

3. Research Objectives 1. Measure structural dynamics of conducting polymers using 2D-VES techniques 2. Look for a correlation between conduction and dynamics out-of-plane motions ~100 - 300 fs torsional motions ~500 fs - 1 ps

4. How will we measure the dynamics? Polymer Chains Porphyrin The Metal-CO stretch is an extremely strong absorber The TPP-porphyrin  -system affords mixing with aromatic  -conjugated polymers Should always be careful with embedded reporters RuTPP

5. FTIR of Polymer films w/ and w/o RuTPP

6. Reporter in Solvent vs. Polymer FTIREcho Decay -Dephasing of the C≡O is much slower in a polymer film than in a solvent -Static frequency shifts in the FTIR indicate a change in the available range of frequencies … this has nothing to do with dynamics!

7. Spectral Diffusion.. in a polyaniline film.. in a NMP -Spectral Diffusion is more pronounced in the solvent solution than it is in the polymer film

8. Reporter in Different Polymer Films

9. Poly (3-Hexylthiophene) or P3HT Regiorandom 1:1 head to head:head to tail linkages Regioregular 98% head to tail linkages RandomRegular Two Forms Head to HeadHead to Tail R=(CH 2 ) 5 CH 3

10. Echo Decays of P3HT Region 1Region 2 Comparison

11. Ideas 1.Crystalline vs. amorphous 2. Ligated vs. non-ligated Ru CO Polymer? 3. Free vs. aggregated RuTPP

12. Conclusions 2DIR-VES is a useful technique for measuring ultra fast polymer motions RuTPP embedded in polymer film is sensitive the changes in dynamics between different polymer films P3HT may have different dynamics in different environments of the film Eventually we hope to measure the dynamics with an electrical voltage applied to the thin films

13. Thanks! Symposium Host: Ohio State and Martin Zanni Advisor: Aaron Massari Group Members: Pat Konold and Dan O’Brien Collaborators: Marc Hillmyer and Bryan Boudouris Funding: n