The goal of Professor Hayes' research group is a basic understanding of the structure and properties of different types of inorganic systems, including semiconductors and other optically and electronically active materials.
Optically-pumped NMR (OPNMR) combines laser excitation with NMR detection, and optically-detected NMR (ODNMR) is the detection of polarized photoluminescence of conduction electrons with the NMR resonance condition is met during a sweep of field or frequency. Electrons are excited into the conduction band and spin polarized by the incident photons. Nuclear spins in the lattice become oriented by the photoexcited electrons through the hyperfine interaction. This nuclear orientation is subsequently detected by NMR (radio-frequency detection) or optically.
Inorganic metal oxides with group 13 metals (Ga, In, Al, B) offer good targets for solid-state NMR analyses. Our group focuses on the characterization of group 13 cluster precursors, and the transformation of the precursors to thin films. Specifically, the group has been investigating and characterizing [Ga13(μ3-OH)6(μ2-OH)18(H2O)24](NO3)15 cluster precursors and the corresponding mixed gallium and indium heterometallic clusters [Ga13-xInx(μ3-OH)6(μ2-OH)18(H2O)24](NO3)15 (x = 1-6) using solid-state NMR.
In situ elevated-pressure and elevated temperature NMR is being developed for examining process in CO2 capture and sequestration. In the former, carbon dioxide is physisorbed and chemisorbed by materials designed for CO2 capture from flue gases and similar sources. We study the structure of such materials, including the chemisorbed products that result and monitor reaction conditions that are favorable. In carbon sequestration, the “mineralization” of carbon dioxide (converting to carbonates, such as calcium carbonate or magnesium carbonate) can be monitored in conditions that mimic environments underground, with elevated pressures and temperatures and in heterogeneous mixtures of brine-soaked minerals.