As fossil fuels remain the major source of energy worldwide, the related emissions are one of the largest contributors to climate change. Consequently, the demand for increased use of solar energy as a clean and unlimited energy source is a priority. Organic photovoltaic (OPV) materials are attractive as cost-effective and sustainable alternatives to silicon solar cells. The objective of this work was to synthesize conjugated polymers with favorable optical and physical properties for use as solar cell materials. Monomer building blocks with electron rich indole and furan/thiophene planar functional groups were studied for ultimate incorporation in donor polymers for OPV cells. The furan functional group was obtained from the sustainable reactant furfural, a material sourced from corn byproducts. We successfully synthesized monomers using a two-step scheme involving Knoevenagel condensation and alkylation reactions. The products were purified by column chromatography and characterized by ESI-MS, X-ray crystallography, and NMR spectroscopy. Isolating these monomers was complicated by their unexpected ability to isomerize in solution at room temperature. Monomer isomers will likely lead to nonlinear polymers with poorer solar absorption efficiency and lower molecular weights. Currently, work in our group is underway to synthesize related structurally rigid monomers that prevent interconversion between isomers to address these difficulties. The resulting rigid, planar polymers will ultimately possess improved properties to construct efficient OPV devices for solar energy production.

Semi-sustainable monomers for organic photovoltaic donor polymers

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.