Collaborative Research: Multifunctional cross-conjugated organic electronic materials.

University Of North Georgia, Dahlonega GA

Investigators

Abstract

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Drs. Malika Jeffries-EL of Boston University and Aimée Tomlinson of the University of North Georgia are developing tunable organic semiconductors. These carbon-based materials combine the optical and electronic properties of conventional inorganic semiconductors with the processibility of polymers. Thus, they can potentially be used in a wide range of applications such as chemical/optical sensors, displays, and solar cells. In this project, the basic chemical structure of a novel molecule with a cross-like motif will be systematically modified to tailor the resulting electronic properties. Computational methods will first be utilized in order to identify the most promising candidates for synthesis and characterization. Synthetic organic chemistry will then be used to prepare these motifs through a series of well-established transformations. Finally, the resulting systems will be characterized using a variety of sophisticated spectroscopic techniques, concluding with the fabrication of devices. The structure-property correlations that will result from this research have the potential to advance fundamental chemistry knowledge in the field of organic electronics. This award provides new opportunities for undergraduate and graduate student training in materials and computational chemistry, with an emphasis on low-income and/or first-generation students. Additionally, a new Boston University Life Sciences Inclusive Excellence Initiative will be launched which seeks to increase STEM degree attainment for underrepresented groups. This program will provide training of faculty in inclusive excellence, with the aim of boosting retention in STEM majors, and increasing longitudinal outcomes, such as entry into post-secondary programs or employment. This research will combine experimental and theoretical approaches to develop new materials based on a unique class of compounds, cross-conjugated benzo[1,2-d:4,5-d’]bisoxazoles (BBO)s. Cross-conjugation is especially useful for developing organic semiconductors as the arrangement of two orthogonal conjugation paths leads to spatial segregation of the frontier molecular orbitals. As a result, the HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) can be modified autonomously. Further strategic positioning of the various (hetero)aromatic rings along the axes of the BBO moiety is expected to enable tuning of the optical and electronic properties of the system through extension of the pi-bond network and through inductive effects from the aryl rings. In this way, it may be possible to tailor cross-conjugated BBOs for use in specific applications including as non-fullerene acceptors in organic photovoltaics, and as blue light-emitters and wide band gap hosts for organic light-emitting diodes (LEDs). This work will be accomplished using a feedback loop that combines theory, synthesis, spectroscopy, and device fabrication to identify and generate new materials. This iterative approach should allow for well-informed access to the target BBOs. Furthermore, the planned structure-property studies have the potential to advance the rational design of new conjugated materials with tunable and predictable optical and electronic properties. This award also will provide new opportunities for undergraduate and graduate student training in materials and computational chemistry, with an emphasis on low-income and/or first-generation students. The PIs will recruit such students through their participation in various activities on their respective campuses. 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.