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My research interests involve studying the fundamental optical properties of nanoscale materials, with the goal of working toward their integration into devices and applications. Specifically, we focus on understanding the fluorescent properties of single-walled carbon nanotubes (SWNTs). SWNTs are hollow cylinders of graphene (Figure 1) that display incredible strength, fascinating electronic properties, and unique optical features. Interestingly, the majority of SWNTs display size-tunable and highly stable fluorescence in the near infrared, which makes them especially relevant for biological imaging and sensing applications.
Figure 1. Depiction of an SWNT as it is
hypothetically rolled up from a graphene sheet.
SWNTs are synthesized as mixtures of particles having different structures, and therefore, optical properties. The study of carbon nanotube fluorescence is complicated by this heterogeneity and the development of straightforward separation techniques is an area of active research. Further, the integration of SWNTs into devices has been hindered because they suffer from defect sites that result during sample processing. Because defect sites can strongly alter the intrinsic behavior of carbon nanotubes, additional research is needed to clarify their exact role on SWNT fluorescence. Research in my laboratory addresses both of these challenges using a combination of chromatographic techniques and optical spectroscopy.