Professor Jean Hubert Olivier of the University of New Mexico

"Repurposing the Structure-Property Relationships of Supramolecular Polymers to Manipulate the Electronic Functions of Nanoscale Objects"

As a product of the dynamic equilibrium between solubilized building blocks and self-assembled structures, supramolecular architectures are fragile compositions where minor changes in temperature, solvent dielectric, and building-block concentration can trigger the dismantlement of superstructures and concomitant loss of their emergent properties. Developing molecular strategies to functionalize non-covalent assemblies at equilibrium and far from equilibrium using chemical fuels can provide entirely new nanoscale platforms to “dial in” structure-function properties that remain vastly elusive by current supramolecular methodologies.

This seminar will introduce design principles to staple 1-dimensional supramolecular polymers in solution. The extent to which this novel approach can be leveraged to modulate the semiconducting properties and light-harvesting capabilities of nanoscale objects will be shown. Exploiting ultrafast transient absorption spectroscopy and spectroelectrochemistry, we will discuss the properties of the excited state products formed following photoexcitation and correlate them to the structural properties of the molecular tethers with which π-conjugated aggregates are stapled. These studies demonstrate that the ability to modulate the electronic structures of nanoscale objects, used in conjunction with facile hierarchical organization, offers exceptional promises for developing optoelectronic materials.

In the last part of the seminar, we will show the molecular engineering of far-from-equilibrium semiconducting superstructures derived from water-soluble, π-conjugated building blocks whose electrical functions are regulated by the consumption of chemical fuels. Our work broadens fuel-driven complex systems that traditionally use small, solvated building blocks by demonstrating that chemical reaction cycles can be performed using non-covalent assemblies as reactive precursors.