Physical Chemistry Seminar: Professor Nandini Ananth, Cornell University, Sapp Center Lecture Hall, 4:30pm (Host: Tom Markland)
About the Seminar:
"Charge Transfer Dynamics, Excited State Energetics, and Organic Photovoltaics"
Designing molecular materials for use as organic photovoltaics, molecular electronics, and photocatalysts is a multifaceted challenge requiring a detailed understanding of both the excited state energetics and the dynamics of charge and energy transfer. We address the dynamic challenge by developing new methods based on the path integral formulation of quantum mechanics that are uniquely suited to the simulation of photo-initiated excited state dynamics in the condensed phase. We then tackle the characterization of the ex- cited state manifold in molecular systems using a combination of high-level electronic structure methods to accurately calculate excited state energies, normal mode analysis to quantify vibronic couplings, and novel orbital analyses to uncover structure-spectrum correlations.
In this talk, we focus on one target application: designing chromophores that exhibit ultrafast Singlet Fission (SF), a phenomenon that has the potential to significantly increase organic solar cell efficiency. We investigate SF in non-bonded and covalently bonded pentacene dimers: we uncover two distinct mechanistic pathways for ultrafast SF and we identify molecular geometries and bonding motifs that can be modified to enhance efficiency in each case. Finally, we combine the insights obtained from our theoretical investigations to generate a priori design principles for next-generation SF chromophores, and working with experimental collaborators, we verify them.
About the Speaker:
Nandini Ananth was born in Chennai, India. She attended Stella Maris College in Chennai, where she majored in chemistry and served as editor of the college newspaper in her senior year. After graduating at the top of her class with a Bachelor's degree in Chemistry, she joined the Masters program in chemistry at the Indian Institute of Technology Madras. Here she developed a strong interest in quantum mechanics and carried out research on implementing logic gates for quantum computing using Nuclear Magnetic Resonance under the guidance of N. Chandrakumar. During this time she also received a Summer Research Fellowship from the Jawaharlal Nehru Center for Advanced Scientific Research and was introduced to semiclassical dynamics in K. L. Sebastian's group at the Indian Institute of Science, Bangalore. This further solidified her interest in theoretical chemistry and chemical dynamics.
Nandini moved to the United States in the fall of 2003 to pursue doctoral research at the University of California, Berkeley in William Miller's group, working on developing semiclassical methods to model quantum dynamical behavior in complex chemical reactions. Upon graduation, she accepted a position as postdoctoral scholar in Thomas Miller's group at the California Institute of Technology, Pasadena, where her research focused on developing path-integral methods for the simulation of electronically nonadiabatic processes in the condensed phase. She joined the faculty of the department of Chemistry and Chemical Biology at Cornell University in the Fall of 2012, and during her time here has received the Cottrell Scholar Award, NSF CAREER Award, NSF EAGER Award, Sloan Research Fellowship, and Army Research Office’s Young Investigator Award.