Multi-State Organic Fluorophores

In this project funded by the Chemical Structure, Dynamics & Mechanisms B Program of the Chemistry Division, Professors Lei Zhu and Kenneth L Knappenberger of the Department of Chemistry and Biochemistry at Florida State University are developing new organic fluorescent molecules that are individually capable of emitting light of different colors. The goal of this research is to understand the fundamental molecular structural requirements that give rise to the unique property of multiple emissions. These multi-emitting molecules can be developed into components of energy-efficient, light-emitting materials. This project lies at the interface of organic, physical, and materials chemistry, and is therefore well suited to the education of scientists at all levels across disciplines in chemistry. This research group is ethnically and culturally diverse, which is also well-positioned to provide the highest level of education and training for students underrepresented in science. Outreach activities include developing short courses targeting non-chemistry students on the societal impact of chemical research, and a summer workshop on training college students on the promises and perils of original research. A multi-state organic fluorophore is one that undergoes ground state equilibria and/or excited state transformations to result in simultaneous fluorescence at different wavelengths (i.e., multiple emission). The goal of this project is to understand the fundamental molecular photophysics of novel multi-state organic fluorophores. By doing so, means to control the overall brightness and color mixing of a multi-fluorescence profile can be developed to afford, for example, white light emission. Bright, near-white light-emitting fluorophores are assessed for their potential utility in electroluminescence-based energy-efficient lighting devices. Fluorophores that are capable of rapid intra- or intermolecular proton transfer either in the excited or the ground state (i.e., proton transfer dyes) are the specific multi-state fluorophores under investigation in this application. The photophysical properties of these compounds are studied by quantum mechanical calculations, steady-state and ultrafast time-resolved spectroscopies. If successful, new fluorescent compounds with utility in white light-emitting materials will be identified.