CAREER: Bifacial Cyclophanes for Solution-Phase Synthesis of Semiconducting Porous Nanoribbons

Georgetown University, Washington DC

Investigators

Abstract

With support from the Macromolecular, Supramolecular and Nanochemistry (MSN) Program in the Division of Chemistry, Professor Nagarjuna Gavvalapalli at Georgetown University designs and develops strategies for bottom-up synthesis of semiconducting porous nano-ribbons (SPNRs). Inspired from the β-sheets design in nature, Professor Gavvalapalli’s group designs novel monomers to enable bottom-up synthesis of SPNRs with control over their ribbon width, conductivity and pore size. SPNRs combine the transistor properties of semiconductors with the sensing and sieving capabilities of nanopores. They can be potentially useful for applications such as high-throughput transport detection, sensing multiple biomarkers of a disease, and energy conversion. The project contributes toward training, educating, and inspiring a diverse group of people including high-school students from underserved communities in science, undergraduate students, and the public. Professor Gavvalapalli develops and uses a “Superhero Scienceplanation” program to tap into people’s interest in and curiosity for superheroes in order to easily connect with a broader audience from diverse backgrounds. Organic SPNRs have several advantages, including single-atom-thickness and synthetic amenability to tune pore size, shape, and chemical functionality compared to traditional solid-state nanopores. However, the current top-down approaches are not suitable for generating SPNRs with control over the nanoribbon and pore dimensions as well as their chemical and electronic structure that are desirable for the above-mentioned applications. The proposed work in Professor Gavvalapalli’s group designs novel building block monomers for SPNRs and develops design rules for bottom-up and solution-phase synthesis of SPNRs with control over the ribbon and pore dimensions as well as their chemical and electronic structure. The monomers are designed such that they hinder interchain van der Waals interactions and render solution processable SPNRs. The three main objectives of the research are focused on: i) varying the monomer design parameters to generate soluble linear-polymers that provide guidelines for SPNRs solubility; ii) identifying and controlling the linear-polymer structural parameters that play a key role in transforming them into SPNRs; and iii) synthesizing SPNRs of various nanoribbon width, pore size, and electronic nature and studying their impact on the photophysical and electronic properties of SPNRs. This research provides access to nanoporous membranes that have been elusive so far. The obtained SPNRs enable transformative changes to above-mentioned technologies and also pave the way to new technologies. 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.