Many of the remarkable features seen in nature, ranging from the strength of spider silk to the light-harvesting ability of plant leaves, arises from sophisticated, multicomponent architectures. These biological nanostructures are comprised of multiple, discrete components that are assembled with nanoscale (one billionth of a meter scale) precision into a highly integrated functional system. Self-assembly offers a convenient, albeit often trial and error-based strategy, to make single-component, synthetic materials in the nanoscale regime. However, these systems rarely exhibit the high level of performance seen in natural systems due to the difficulties in reliably designing self-assembling systems composed of multiple, precisely positioned components. To address this challenge and progress toward higher levels of functional performance, Professors Parquette of The Ohio State University and Modarelli of The University of Akron, are developing strategies to self-assemble multiple, discrete building blocks into multicomponent architectures to serve as optoelectronic materials for solar energy conversion. Creating reliable strategies to create non-covalent architectures that rival the sophisticated systems in biology may enable new technologies capable of addressing societal problems in areas such as renewable energy, greenhouse gas conversion, and medicine. Additionally, this project is used as a platform to enhance public awareness of the potential role that science plays in addressing these issues. The research team continues to present science exhibitions at the Columbus Center of Science and Industry (COSI) to allow younger students to experience the hands-on excitement of scientific discovery. Also, the investigators use Ohio State's REEL program to offer opportunities for large numbers of undergraduate students to perform nanotechnology research in a teaching laboratory environment in addition to providing opportunities for undergraduates in the research laboratory. Professors Parquette and Modarelli provide research experiences to minority students in the area of nanotechnology through the NSF HBCU-RISE program and through the SROP (Summer Research Opportunities Program) at OSU.
The Macromolecular, Supramolecular and Nanochemistry Program of the Chemistry Division supports the work of Professors Parquette and Modarelli, which aims to develop a versatile strategy to assemble multiple optoelectronic components into self-sorted domains that are integrated within a single nanostructure. This approach creates composite nanostructures using a sequential layer-by-layer strategy to organize pre-assembled systems into one architecture. The morphology, dimensions, and positional arrangement of the components are correlated with the corresponding photophysical properties, measured using ultrafast spectroscopic techniques. The research activities include: (1) the co-assembly of nanotube-polymer composites displaying a coaxial, bicontinuous array of conjugated polymers that establish a redox cascade; (2) the co-assembly of discrete, monomeric building blocks into composite structures comprised of separate, self-assembled nanostructures; (3) measurement of the photophysical properties of the assemblies via ensemble and single-molecule femtosecond spectroscopy; and (4) to measure photo-electrochemical coupling of aligned nanotube co-assemblies via surface-tracked scanning electrochemical microscopy (ST-SECM).This project integrates fundamental research with outreach and communication efforts to engage a diverse group of students in interdisciplinary science, and the community at large, to show how nanotechnology impacts their lives.
