Excellence in Research: Electroactive Oligofluorenes and Cofacially pi-Stacked Polyfluorenes

NON‑TECHNICAL SUMMARY: Modern electronic devices rely on materials that can efficiently move electrical charge. Organic materials, which are made from carbon-based molecules, offer exciting possibilities for lightweight, flexible, and low‑cost electronics. However, scientists still lack a clear understanding of how charge moves through organic structures. This project investigates a special class of organic molecules that naturally align in a defined arrangement. This alignment allows electrons (i.e., electrical charge) to move more easily from one unit to another, like how charge travels in DNA. By learning how to stabilize charged states and control electron flow, this project will advance the development of molecular wires that could one day support faster, more efficient semiconductor technologies. This project strengthens the scientific infrastructure at Prairie View A&M University, and the research will be further elevated through a collaboration with researchers at Texas A&M University. Students will participate directly in cutting‑edge materials research which will contribute to National interests by expanding educational opportunities and supporting workforce development in materials chemistry and semiconductor research. Outreach activities include K‑12 engagement and public science events. TECHNICAL SUMMARY: This collaborative project investigates charge transport and electronic coupling in cofacially stacked oligofluorene systems decorated at their periphery by various functionalities. The research, which aims to establish fundamental relationships between molecular structure and electronic properties, consists of three integrated objectives. The first objective is to synthesize difluorene platforms incorporating boron and chalcogen substituents to investigate the formation and electronic properties of odd-electron element-element sigma bonds. The second objective is to determine how molecular architecture influences hole transport through controlled oxidation, spectroscopic characterization of radical cation species, and intervalence charge-transfer studies in cofacially stacked oligofluorenes. The third objective is to develop fluorene and diazafluorene derivatives with reduced lowest unoccupied molecular orbital energies to facilitate electron transport, stabilize radical anions, and evaluate n-type charge-transport behavior. The project combines organic synthesis with cyclic voltammetry, ultraviolet-visible-near infrared spectroscopy, electron paramagnetic resonance spectroscopy, X-ray crystallography, scanning electron microscopy, atomic force microscopy, thin-film characterization, and single-molecule conductance measurements to establish quantitative structure-property relationships governing charge delocalization, redox behavior, and electronic conductivity. The outcomes will expand the electronic landscape of organic semiconductor materials and provide fundamental insights relevant to molecular electronics, optoelectronics, and nanoscale charge‑transport design. Students will participate directly in cutting‑edge materials research which will contribute to National interests by expanding educational opportunities and supporting workforce development in materials chemistry and semiconductor research. Outreach activities include K‑12 engagement and public science events. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.