Collaborative Research: New Approaches to Narrow-Band Electrochromics

In this project, funded by the Chemical Structure, Dynamics & Mechanism B Program in the Division of Chemistry and the Electronic and Photonic Materials program in the Division of Materials Research, Professors Seth Marder at Georgia Tech and Colleen Scott at Mississippi State University are developing new approaches to molecules that can be reversibly switched between vividly colored and colorless states using an electrical stimulus. Such materials may have applications in displays, “smart windows”, eye and sensor protection, and optical communications.

As well as potentially impacting academic and industrial efforts relating to these applications, this work will also lead to new knowledge relating to the coupling of bond breaking/formation and electron-transfer processes. Further broader impacts will result from the training of students in chemical synthesis and characterization, and in electrochemical and optical characterization of materials, as well as through their ongoing activities relating to broadening participation, including mentoring minority students and early career faculty, and engaging in outreach to K-12 classrooms.

While many materials are electrochromic, very few are switchable between essentially colorless and vividly colored states, as required for high-contrast displays and some photonic applications. The proposed work involves covalent linking of a metallocene “electrophore” and a chromophore based on a rhodamine or a related structure that can be switched between a colorless ring-closed form and a ring-opened form that is vividly colored due to a high-absorptivity narrow absorption band.

In contrast to many other electrochromic systems, the electrochemical and optical properties can be independently tuned and optimized. The Marder and Scott research groups will explore a variety of alternative approaches in which the one-electron oxidation of ferrocene to ferrocenium (both of which are very weakly absorbing relative to the open forms of the chromophores), or the two-electron oxidation of a ruthenocene derivative, is coupled to ring-opening or closing of the dye so that the dyes are either anodically (i.e. oxidatively) or cathodically (i.e. reductively) coloring.

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.