AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Supramolecular Self-assembly of Photosynthetic Dyes in Aerosolized Droplets
VIVEK SHAH, Pratim Biswas, Washington University in St. Louis
Abstract Number: 284 Working Group: Nanoparticles and Materials Synthesis
Abstract Self-assembled materials often have properties very different than that of individual molecules. For example, excitonic transfers can take place only in self-assembled chlorin molecules. Hence they are of interest in photonics, opto-electronics and solar cells (Modesto-Lopez et al., 2010). Materials with high order, which is characteristic of self-assembled materials, are hard to synthesize by covalent chemistry. Various solution-based techniques have been developed for supramolecular self-assembly (Mass et al., 2011; Miyatake & Tamiaki, 2010). Due to mixing the structural growth is hard to control. A one step aerosol-based self-assembly technique has been developed, to overcome limitations of solution-based techniques. Although aerosol routes have been used to self-assemble mesoporous structure, not much work has been done on supramolecular assembly.
In this study, the photosynthetic dye molecules are dissolved in a solvent which is atomized by electrospray. The monomers assemble in the droplets as the solvent evaporates. After the solvent evaporates, the agglomerates are deposited onto a transparent substrate. These agglomerates, when self-assembled, show a characteristic red-shift in absorption compared to their monomers. Experiments show that electrospray-based technique is a promising method to synthesize self-assembled structures and the results are explained with help of the classical nucleation theory. Results show that in case of single solvent, the evaporation time should be longer than nucleation time for the assembly to take place. Further control over the size of nucleated self-assembled structures can be obtained by judiciously selecting the spray solvents and the initial concentration of dye.
Modesto-Lopez, L.B., Thimsen, E.J., Collins, A.M., Blankenship, R.E., & Biswas, P. (2010). Energy Env. Sci., 3, 216-222.
Mass, O., Pandithavidana, D.R., Ptaszek, M., Santiago, K., Springer, J.W., Jiao, J., Tang, Q., Kirmaier, C., Bocian, D.F., Holten, D., & Lindsey, J.S. (2011). New J. Chem., 35, 2671-2690.
Miyatake, T., & Tamiaki, H. (2010). Coord. Chem. Rev., 254, 2593-2602.