Research Overview: Our group focuses on the photochemistry and photophysics of inorganic and organometallic compounds, with emphases on fundamental control of excited-state dynamics in photoluminescent compounds, the design of photosensitizers for photocatalysis applications, and luminescent sensors for molecular oxygen. Researchers in our group gain experience in organic, inorganic, and organometallic synthesis, physical characterization techniques that include multinuclear NMR and X-ray crystallography, cyclic voltammetry, and a variety of photphysical techniques that include UV–vis absorption spectroscopy and steady-state and time-resolved photoluminescence measurements on a variety of sample types. Additional details about our major focus areas are given below.
Photoluminescence: We are developing molecular design strategies to control the radiative and nonradiative rate constants in phosphorescent organometallic compounds. We ar especially emphasizing phosphorescence in the extremes of the spectrum — deep blue and red to near-infrared. Top-performing candidates are tested as emissive dopants in organic light-emitting diodes.
Photoredox Catalysis: Using strongly photoreducing cyclometalated photoreductants previously discovered in our group, we are developing a range of photoredox transformations on substrates that are challenging to reduce. These include transformations of unactivated organohalide substrates and C–C or C–H bond-forming reactions using challenging carbonyl or imine substrate classes.
Earth-Abundant Photosensitizers: In one of the newest efforts in our group, we are developing earth-abundant, copper(I) charge-transfer photosensitizers supported by β-diketiminate and other electron-rich chelating ligands. At this stage the work is fundamental in nature and focuses on strategies to control the redox potentials and the energy of the charge-transfer excited states to optimize solar light harvesting, and approaches to extend the excited-state lifetimes and improve photocatalytic performance.
Ratiometric O2 Sensors: Using synthetic strategies that allow rapid assembly of bichromophore structures that feature a phosphorescent cyclometalated iridium center tethered to an organic fluorophore, we are designing and characterizing a large library of ratiometric oxygen sensors. By exerting synthetic control over the photoluminescence wavelengths and lifetimes, we are able to control the signal resolution, sensitivity, and dynamic ranges of the sensors.
