My interests span analytical chemistry, inorganic chemistry, surface science, and sold-state materials science. Current research in the Van Ryswyk group centers around three major thrusts:
- Dye-sensitized solar cells utilizing porphyrin dyes on nanostructured zinc oxide. We use zinc oxide nanoparticles, nanorods, and nanotubes as the photoanode in combination with a range of zinc porphyrins to better understand the interactions of dye and photoanode in dye-sensitized solar cells (DSSCs). The ultimate goal is to create low-cost photovoltaics that can be produced easily for large-area applications. We do organic and inorganic synthesis, nanoparticle synthesis, and utilize MALDI-TOF MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrscopy), scanning electron microscopy, and a wide range of visible and near infrared spectroscopy techniques to characterize our materials and the final test cells. Current generation DSSCs are 11% efficient; a 20% efficient DSSC would be a truly “disruptive technology” with respect to global energy supply. For more information concerning the global energy prospective, see Prof. Nate Lewis’ resources.
- Experimental investigation of electronic coupling in metalloporphryin dimers and trimers. We use solid-phase organic synthesis, photolysis, and inert atmosphere (glove box) techniques to synthesize metalloporphyrin dimers and trimers. We study the metal-to-metal electronic coupling in these oligomers via observation of the near-infrared intervalence charge-transfer bands in order to make comparisons to predictions generated by Prof. Cave’s group using their recently developed Koopmanns’ Theorem – Generalized Mulliken Hush approach (KT-GMH) based upon semiempirical, Hartree-Fock, and Density Functional Theory-based calculations.
- Lead levels in soil from vehicle emissions. Lead in soil from vehicle emissions is a leading cause of childhood lead poisoning in southern California. We developed a service-learning module for the general chemistry course at HMC wherein our first-year students work with local fifth- and sixth-grade students to determine lead levels in soil throughout our community. We utilize statistical sampling methods, GPS mapping, microwave-assisted digestion, and atomic absorption analysis in a preliminary study of soil at the Bernard Field Station adjacent to old U.S. Route 66 in Claremont. We are working with Vista del Valle, Oakmont, Mountain View, and Sumner elementary schools in the Claremont Unified School District. See the Vista del Valle – Harvey Mudd College Collaboration in Science, Mathematics, and Writing for more information.
All of the work described here is done at Harvey Mudd College with undergraduate coworkers. An example of recent research in my laboratory is shown below (*denotes undergradute co-author):
- R.A Jensen, H. Van Ryswyk, C. She, J.M. Szarko, L.X. Chen, J.T. Hupp, “Dye-sensitized solar cells: sensitizer-dependent injection into ZnO nanotube electrodes,” Langmuir 2010, 26, 1401-1404.
- T.W. Hamann, R.A. Jensen, A.B.F. Martinsen, H. Van Ryswyk, and J.T. Hupp, “Advancing Beyond Current Generation Dye-Sensitized Solar Cells,” Energy Env. Sci. 2008, 1, 66-78. [PDF]
- Van Ryswyk, Hal; *Moore, Erin E.; *Joshi, Neel S.; *Zeni, Rebecca J.; Eberspacher, Todd A.; Collman, James P. “Surface-confined metalloporphyrin oligomers.” Angewandte Chemie Int. Ed. 2004, 43, 5827-5830. [PDF]
- Van Ryswyk, H.; *Gabor, R. S.; *Awasthi, S.; *Bodzin, D. J.; *Orosz, K. S. “Kinetics of metalloporphyrin chemisorption onto monolayer-confined ligands and subsequent distal ligand exchange.” Langmuir 2004, 20, 11815-11817. [PDF]
- Eberspacher, Todd A.; Collman, James P.; Chidsey, Christopher E.D.; *Donohue, Deirdre L.; Van Ryswyk, Hal “Modular assembly and air-stable electrochemistry of ruthenium porphyrin monolayers” Langmuir 2003, 19, 3814-3821. [PDF]
Keywords: monolayer and multilayer self-assembly; dye-sensitized solar cells; photovoltaics, photoelectrochemistry, electronic coupling, quantum dots.