MRI: Track 1 Acquisition of a turnkey transient absorption spectrometer for undergraduate research and training

Furman University, Greenville SC

Investigators

Abstract

This award is funded by the Major Research Instrumentation Program and the Chemistry Research Instrumentation Program. Professor Lauren Jarocha from Furman University and Professors Pin Lyu and Christian Kerpal from the University of North Carolina – Asheville, on behalf of nine investigators at both institutions, are acquiring a turnkey, sub-nanosecond transient absorption spectrometer. Transient absorption (TA) is a pump-probe form of spectroscopy, where a sample is excited with a pulsed laser, then the new chemical species produced are investigated using a probe light source. This experimental technique is an essential tool for photochemists, spectroscopists, and molecular physicists for following reaction progress in real time. It will be used to develop new types of catalysis, antimicrobial agents, solar energy capture, molecular sensors, biological imaging, and light-based remediation of environmental pollutants. The instrument will enhance the educational experiences at two primarily undergraduate institutions, allowing undergraduate students to develop relevant and important skills that lead to success in their future careers. The TA spectrometer will support research projects that are varied, but all utilize the instrument’s capabilities to identify excited state species and follow molecular dynamics in real time. In the case of Professor Jarocha’s and Professor Kerpal’s research, the instrument will be used to help establish the fundamental structural, dynamic, and kinetic properties of radical pairs that allow them to act as efficient, quantum-based molecular sensors. Proof of principle experiments that a radical pair can function as a molecular compass comes from measurement of an orientation-dependent response to Earth strength fields in radicals formed on a carotenoid-porphyrin-fullerene triad. The sub-nanosecond time resolution of this instrument will enable the study of similar magnetically sensitive reactions in a time-regime that has not been well characterized. This will allow a more complete understanding of the mechanisms by which magnetic fields can alter reaction rates or product yields and will help in the design of novel materials that behave as molecular sensors for use in future devices. Professor Lyu’s research is focused on transforming solar energy into storable fuels, leveraging the instrument to develop novel nanomaterials for photocatalysis. The Lyu lab is pursuing a Janus strategy to design the metal-semiconductor hybrid structure, with the idea that this structure should increase the lifetime of photoexcited electrons produced by UV or visible light due to the larger interface for electron injection and the larger metal electron reservoir. With a longer lifetime, photoexcited electrons should have a higher probability of participating in reduction reactions, thus improving photocatalytic activity. Additionally, the spectrometer will support research focused on informed design of first-row, d0 transition metal catalysts; development of new sensors based on biotemplated metal nanoparticles; synthesis of natural products that act as antimicrobial agents; exploration of new polymorphs of titanium dioxide as catalysts for the degradation of volatile organic pollutants; improvement of device efficiency in organic solar cells based on green solvent processing polymers; and development of fluorescent biosensors based on hybrid polymer liposome-quantum dot nanomaterials. All research is primarily conducted by undergraduate students. Therefore, access to and training on this instrument supports the development of a diverse STEM workforce prepared to solve problems of serious social significance. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.