Rebecca L. M. Gieseking
Assistant Professor of Chemistry
Northwestern University, Postdoc
Georgia Institute of Technology, Ph.D.
Furman University, B.S. and M.S.
Rebecca Gieseking will be starting summer/fall 2018
Our research is focused on developing computational models to understand materials for emerging energy technologies in the fields of solar energy, batteries, and fuel generation. The critical steps in these technologies involve electron transfer at complex interfaces. We will focus on using theoretical and computational approaches to reveal design principles that connect molecular structure to the important material properties required for these applications, with the goal of developing an understanding that can be used to guide experimental studies.
Realizing new energy technologies based on photochemistry and electrochemistry requires developing materials with properties that increase device efficiencies and performance, and in particular understanding how the molecular and material structure can be tuned to achieve these properties. The key processes underlying these technologies involve heterogeneous charge transfer induced by either light or electrical potential. Our particular emphasis is on charge transfer processes at interfaces between inorganic solids and molecules in solution. Computational and theoretical techniques provide powerful tools to gain atomic-level insight into these properties that is difficult to obtain experimentally, particularly in these complex non-uniform environments.
The Gieseking group develops and implements multi-scale approaches combining quantum mechanical and classical molecular dynamics methods to develop understanding of the photochemical and electrochemical properties and dynamics of materials with applications in energy technologies. Although our work involves a broad range of computational approaches, our development efforts focus primarily on semiempirical methods, which can predict charge-transfer energies more accurately than typical DFT functionals due to their lack of self-interaction error at a substantially lower computational cost.
The goal of our work is to use our computational tools, in collaboration with researchers in experimental materials synthesis and characterization, to develop material design principles that will aid in accelerating the development of materials with controlled properties.
Photochemistry and Excited-State Dynamics
Storing solar energy as chemical fuels is critical to reduce our dependence on fossil fuels and meet increasing energy demands. Photocatalytic synthesis of these fuels typically involves photoinduced electron transfer between the catalyst and the reactant molecule, which can occur via two mechanisms: (1) direct excitation to a charge-transfer state, and (2) an indirect process in which excitation of the metal generates hot charge carriers, which transfer to the acceptor. We are particularly interested in photocatalysis involving plasmonic metal nanostructures because of their strong and highly tunable absorption spectra. Our work on understanding the excited-state dynamics in these systems is aimed toward understanding the structural features that influence the mechanism, yield, and lifetime of the charge-transfer state to enable rational tuning of these structures to enhance photocatalysis.
Reactions at electrochemical interfaces are critical for energy technologies such as fuel generation and next-generation batteries. In many cases, the efficiency of these technologies is limited by large overpotentials and limited selectivity for the desired products. We are developing computational approaches that allow us to explore a broad range of possible reaction mechanisms at electrochemical interfaces, gaining understanding of the features of the electrode surface and solution composition that can be tuned to optimize the efficiency of these reactions for improved device performance.
Yilmaz, M.; Babur, E.; Özdemir, M.; Gieseking, R. L.; Dede, Y.; Tamer, U.; Schatz, G. C.; Facchetti, A.; Usta, H.; Demirel, G. “Nanostructured Organic Semiconductor Films for Molecular Detection through Surface-Enhanced Raman Spectroscopy.” Nature Materials 2017, 16, 918-924. Featured in News and Views: Lombardi, J. R. “Raman spectroscopy: Enhanced by organic surfaces.” Nature Materials 2017, 16, 878-880.
Gieseking, R. L.; Ratner, M. A.; Schatz, G. C. “Theoretical Modeling of Voltage Effects and the Chemical Mechanism in Surface-Enhanced Raman Scattering.” Faraday Discussions 2017, 205, 149-171.
Shiring, S. B.; Gieseking, R. L.; Risko, C.; Brédas, J. L. “Assessment of Front-Substituted Zwitterionic Cyanine Polymethines for All-Optical Switching Applications.” Journal of Physical Chemistry C. 2017, 121, 14166-14175.
Gieseking, R. L.; Ratner, M. A.; Schatz, G. C. “Semiempirical Modeling of Electrochemical Charge Transfer.” Faraday Discussions 2017, 199, 547-563.
Gieseking, R. L.; Ratner, M. A.; Schatz, G. C. “Implementation of INDO/SCI with COSMO implicit solvation and benchmarking for solvatochromic shifts.” Journal of Physical Chemistry A 2016, 120, 9878-9885.
Gieseking, R. L.; Ratner, M. A.; Schatz, G. C. “Quantum Mechanical Identification of Quadrupolar Plasmonic Excited States in Silver Nanorods.” Journal of Physical Chemistry A 2016, 120, 9324-9329.
Gieseking, R. L.; Ratner, M. A.; Schatz, G. C. “Review of plasmon-induced hot-electron dynamics and related SERS chemical effects.” Frontiers of Plasmon Enhanced Spectroscopy Volume 1 2016, ACS Symposium Series 1245, 1-22. Editors: Yukihiro Ozaki, George C. Schatz, Duncan Graham, and Tamitake Itoh. (Cover Article)
Knippenberg, S.; Gieseking, R. L.; Rehn, D. R.; Mukhopadhyay, S.; Dreuw, A.; Brédas, J. L. “Benchmarking Post-Hartree Fock Methods to Describe the Nonlinear Optical Properties of Polymethines: An investigation of the accuracy of Algebraic Diagrammatic Construction (ADC) approaches.” Journal of Chemical Theory and Computation 2016, 12, 5465-5476.
Gieseking, R. L.; Ratner, M. A.; Schatz, G. C. “Semiempirical Modeling of Ag Nanoclusters: New Parameters for Optical Property Studies Enable Determination of Double Excitation Contributions to Plasmonic Excitation.” Journal of Physical Chemistry A 2016, 120, 4542-4549. (ACS Editor’s Choice)
Gieseking, R. L.; Ravva, M. K.; Coropceanu, V.; Brédas, J. L. “Benchmarking Density Functional Theory Approaches for the Description of Symmetry-Breaking in Long Polymethine Dyes.” Journal of Physical Chemistry C 2016, 120, 9975-9984.
Gieseking, R. L.; Ensley, T. R.; Hu, H.; Hagan, D. J.; Risko, C.; Van Stryland, E. W.; Brédas, J. L. “Nonlinear Optical Properties of XPh4 (X = B-, C, N+, P+): A New Class of Molecules with a Negative Third-Order Polarizability.” Journal of the American Chemical Society 2015, 137, 9635-9642.
Gieseking, R. L.; Risko, C.; Brédas, J. L. “Distinguishing the Effects of Bond-Length Alternation vs. Bond-Order Alternation on the Nonlinear Optical Properties of π-Conjugated Chromophores.” Journal of Physical Chemistry Letters 2015, 6, 2158-2162.
Gieseking, R. L.; Mukhopadhyay, S.; Risko, C.; Marder, S. R.; Brédas, J. L. “Effect of Bulky Substituents on Thiopyrylium Polymethine Aggregation in the Solid State: A Theoretical Evaluation of the Implications for All-Optical Switching Applications.” Chemistry of Materials 2014, 26, 6439-6447.
Gieseking, R. L.; Mukhopadhyay, S.; Shiring, S. B.; Risko, C.; Brédas, J. L. “Impact of Bulk Aggregation on the Electronic Structure of Streptocyanines: Implications for the Solid-State Nonlinear Optical Properties and All-Optical Switching Applications.” Journal of Physical Chemistry C 2014, 118, 23575-23585.
Barlow, S.; Brédas, J. L.; Getmanenko, Y. A.; Gieseking, R. L.; Hales, J. M.; Kim, H.; Marder, S. R.; Norwood, R. A.; Perry, J W.; Risko, C.; Zhang, Y. “Polymethine Materials with Solid-State Third-Order Optical Susceptibilities Suitable for All-Optical Signal-Processing Applications.” Materials Horizons 2014, 1, 577-581. (Cover Article)
Gieseking, R. L.; Mukhopadhyay, S.; Risko, C.; Brédas, J. L. “Impact of the Nature of the Excited-State Transition Dipole Moments on the Third-Order Nonlinear Optical Response of Polymethine Dyes for All-Optical Switching Applications.” ACS Photonics 2014, 1, 261-269.
Gieseking, R. L.; Mukhopadhyay, S.; Risko, C.; Brédas, J. L. “Design of Polymethine Dyes for All-Optical Switching Applications: Guidance from Theoretical and Computational Studies.” Advanced Materials 2014, 26, 68-84.
Arman, H. D.; Gieseking, R. L.; Hanks, T. W.; Pennington, W. T. “Complementary Halogen and Hydrogen Bonding: Sulfur···Iodine Interactions and Thioamide Ribbons.” Chemical Communications 2010, 46, 1854-1856.
Gieseking, R. L.; Risko, C.; Marder, S. R.; Brédas, J. L. “Understanding the relationships among molecular structure, excited-state properties, and polarizabilities of π-conjugated chromophores.” The WSPC Reference on Organic Electronics: Organic Semiconductors 2016, vol. 1, 393-420. Editors: Jean-Luc Brédas and Seth Marder.
Tsang, J. S.; Jentsch, E.; Gieseking, R.; Seeger, A. “Preserving Modern Marvels.” Journées d’etudes de la SFIIC, 2009, 125-130.