[Seminar] "THz Spectroscopy: Studying Carrier Dynamics in Nanostructured Materials for Solar Energy Conversion " by Prof. Charles Schmuttenmaer
Terahertz spectroscopy has proven itself to be an excellent non-contact probe of charge injection and conductivity with sub-picosecond time resolution. One may exploit this capability to study a variety of materials, and here we choose to probe the transient photoconductivity of dye-sensitized nanostructured wide band gap semiconductors as well as lower band gap metal oxides such as WO3 and SnO2. These systems are of interest in the area of renewable energy research and artificial photosynthesis.
In addition, we have recently shown that it is possible to probe a fully functioning dye-sensitized solar cell by using patterned transparent conductive oxide (TCO) electrodes. The standard TCO electrodes transmit visible light, but reflect THz light, and are in fact often used as dichroic mirrors in THz experiments. Our results show that it is possible to probe a DSSC while applying a bias voltage and/or under steady state illumination. Our most recent results demonstrate a full 3-electrode THz-transparent electrochemical cell.1
1Coleen T. Nemes, John R. Swierk, and Charles A. Schmuttenmaer, (2018) Analyt. Chem., 90:4389 – 4396. DOI: 10.1021/acs.analchem.7b04204.
Charles Schmuttenmaer joined Yale University in 1994 where he is currently a Professor of Chemistry. He is a pioneer in development and applications of terahertz (THz) spectroscopy. Prof. Schmuttenmaer is a member of the American Chemical Society, the American Physical Society, the Royal Society of Chemistry, and the American Association for the Advancement of Science. He was inducted as a Fellow of the AAAS in 2015, the APS in 2016, and the RSC in 2019.
His current research interests include novel applications of time-resolved THz spectroscopy (TRTS) and THz time-domain spectroscopy (THz-TDS). In particular, he has exploited the unique features of TRTS to characterize the efficiency of electron injection in dye-sensitized photoelectrochemical cells (DSPECs), as well as transient photoconductivity in semiconductors, quantum dots, nanoparticles, and conductive metal oxide frameworks (MOFs). A second major research area involves THz-TDS to probe and understand the low-frequency collective vibrational modes in organic molecular crystals.