Research in the Wustholz group focuses on using spectroscopy to probe the optical and structural properties of chromophores in environments that are inherently heterogeneous. In particular, we study organic dyes in proximity to semiconductor and noble metal nanoparticles for applications to solar energy conversion and chemical sensing.
- Interfacial electron transfer (ET) processes dictate the efficiency of materials and devices that are used to harness solar energy. We are paricularly interested in elucidating the ET kinetics in dye-sensitized systems for applications to solar cells and artificial photosynthesis. By employing single-molecule spectroscopy, we can probe the full distribution of ET behavior occurring at the heterogeneous dye-semiconductor interface. These studies are supported by robust statistical analysis and computational modeling. In another project, we are determining the structure-property relationships of organic dye aggregates on semiconductor films. These studies will inform the design and development of next-generation materials for solar-to-electrical and solar-to-fuel conversion.
- Light-induced degradation of organic dyes is a substantial challenge for a wide variety of applications ranging from solar energy conversion to art conservation. We are particularly interested in the fading properties of substituted anthraquinones, which have been ubiquitous artists' materials since antiquity. In particular, we use single-molecule, UV/vis, and fluorescence spectroscopies to elucidate the photophysical and phochemical pathways that lead to irreversible fading (photobleaching) as well as probe the environmental heterogeneity of paint. This work informs the development of reversible conservation strategies and stable organic-based materials for solar energy conversion.
- Identifying fugitive organic pigments in art is a tremendous analytical challenge. For example, organic dyes and pigments used in historic oil paintings are highly susceptible to fading and are present in exceedingly small quantities. We develop novel surface-enhanced Raman spectroscopy (SERS) strategies to detect and identify fugitive organic pigments in art. These projects are performed in close
collaboration with Shelley Svoboda, Paintings Conservator at Colonial