Department of Chemistry and Biochemistry
Organic/Inorganic/Materials Seminar Series

Professor Niya Sa, University of Massachusetts
February 29th ~ 3:00 pm, 125 McKenzie Hall
Hosted by Paul Kempler

Probe the Dynamic Interfaces of Beyond Lithium-ion Energy Storage Systems

Rapid growth of technology in the past few decades has spurred a demand for advanced energy storage devices. The invention of a more advanced battery system with higher levels of performance will be a groundbreaking discovery in the rechargeable battery field. Multivalent chemistry offers promising benefits in the development of beyond lithium-ion technologies. The direct usage of the multivalent metal anode is essential to enhance the energy density of the multivalent ion battery. For instance, Magnesium, Calcium and Zinc offer an immense alternative to the existing Li-ion batteries due to their multivalent nature and vast abundance in the Earth’s crust. However, possible film formation at the solid/liquid interface complicates the electrochemical properties of such systems. The least understood solid electrolyte interphase (SEI), its formation and dynamic evolution has not been extensively explored for multivalent battery systems with many unknowns remain to be answered. We aim to use electroanalytical tools to probe the dynamic evolution of the solid electrolyte interface in-situ for multivalent systems and investigate its correlation with the electrochemical processes. This presentation focuses on some very recent research findings from our team for understanding the interfacial chemistry, evolution, and stability for different multivalent battery systems.

Department of Chemistry and Biochemistry
Physical Chemistry Seminar Series

Professor Jessica Anna, University of Pittsburgh
February 26, 2024—2:00pm
Tykeson 140

Elucidating Photoinduced Processes and Ultrafast Dynamics of Natural Light Harvesting Complexes and Model Systems

Photosynthetic organisms have developed the molecular level machinery to efficiently and effectively harvest solar energy. To accomplish this, they use natural multichromophoric assemblies called light harvesting complexes to absorb photons and transfer the excitation energy to reaction centers where charge separation can take place with a high quantum efficiency. Elucidating the mechanism of energy transfer and electron transfer in these complexes is essential to (1) understanding
their high quantum efficiencies and subsequently (2) incorporating this information into design principles for artificial photosynthetic systems and photocatalysts. However, given the complexity of natural light harvesting complexes, there are still questions regarding the mechanism of energy and electron transfer in these systems. In this talk I will discuss our recent studies in this area where we apply ultrafast pump-probe and multidimensional spectroscopies in the visible and mid-IR spectral regions to photosystem I, a large natural light harvesting complex, and structurally simpler model systems that mimic specific properties of light harvesting complexes, including artificial light harvesting chromophores, isolated cofactors, and transition metal complexes. From our studies we gain insight into pathways of energy equilibration among different electronic states, information on solvation dynamics, and insight into how non-covalent interactions and spatial confinement  can act to alter the properties and dynamics of molecules.