In this International Collaboration in Chemistry between US Investigators and their Counterparts Abroad (ICC) project funded by the Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division and the Office of International Science and Engineering, Vincent Rotello of the University of Massachusetts at Amherst develop new strategies for assembling quantum dots to be used with flavin-modified polymers to effect charge separation in organic photovoltaic systems. The approach is to form nanopillars of quantum dots using nanoimprint lithography followed by post-processing to decrease interparticle spacing, to interface these particles with flavin-based acceptor macromolecules, and then to fabricate and test the aforementioned compounds in ordered heterojunction photovoltaic devices. This work includes an international collaboration with Prof. Ifor D. W. Samuel of the University of Saint Andrews, U.K. and Prof. Graeme Cooke of the University of Glasgow, U.K. Profs. Samuel's and Cooke's work will be funded by the Engineering and Physical Sciences Research Council (EPSRC). The broader impacts involve training graduate students, enhancing infrastructure for research and education through establishment of an international collaboration between universities in the U.S. and the U.K. The U.S. PI will endeavor to broaden participation of underrepresented groups in science by working with the LSAMP and SURE REU Programs at UMass.
Organic material-based solar cells show great technological promise but have significant drawbacks in terms of low efficiencies and significant processing problems. This research will enhance our fundamental understanding about how the integration of organic compounds and inorganic nanoparticles can be used to capture light and turn it into electrical energy. Through development of new chemical components and processing strategies, this research could lead to easier to process and less expensive solar cell technologies.
Our research has focused on the creation of solar cells using new materials. We had two main thrusts. The first thrust focused on developing new molecules for better harvesting the solar spectrum. Our initial studies focused on the use of molecules related to riboflavin, a naturally occuring vitamin. We used these systems as starting points to develop new molecules that feature light absorption in regions of the solar spectrum that are not well-utilized by current dyes. These studies have yielded new dyes that have been incorporated into solar cells, providing effective systems entirely different than current approaches. The second area we have looked at is the assembly of the components required for solar cells into useful and effective structures. For these studies we used strategies derived from nature, including engineered interactions inspired by base pairing in DNA. Using these strategies we have developed new architectures that provide the right degree of mixing of the components, and are promising leads for future solar cell design.We have also recently extended these studies to the generation of photovoltaic systems by inkjet printing, providing a promising route to inexpensive solar cell manufacturing strategies. In terms of broader impacts, we have provided a platform for the internationalization of science. Students from the US traveled to Scotland, performing research at both Glasgow and St. Andrew. These studies were educational scientifically, and also exposed the researchers to entirely different environments both socially and research-wise.
