TODAY at 4:30 pm in 36-428
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CENTER FOR EXCITONICS
Seminar Series
http://www.rle.mit.edu/excitonics/events/833/
Unusual Solar Photoconversion: Sensitized Triplet Fusion
March 10, 2015 at 4:30 PM/ RLE Haus 36-428
Felix Castellano
Department of Chemistry, North Carolina State University
[castellano_02]
abstract:
One focus of our research program involves the study of sensitized triplet fusion (TF) in
solution using highly photostable metal-organic chromophores in conjunction with
energetically appropriate organic molecules with large singlet-triplet gaps. Selective
excitation of the long-wavelength absorbing sensitizer efficiently generates long-lived
triplet states that serve as energy transfer donors. In the presence of appropriate
molecular acceptors, diffusion controlled triplet-triplet energy transfer takes place,
producing the excited triplet state of the acceptor while regenerating the ground state of
the sensitizer. When sufficient numbers of the sensitized triplets are produced, TTA takes
place which results in either frequency upconverted light or the formation of desired
chemical products. Various combinations of donor and acceptor have been explored and data
will be presented on a number of these systems spanning light conversions ranging from the
near-visible to the near-IR. This presentation will also describe many examples of
upconversion phenomena realized in solid-state polymeric materials along with emerging
classes of acceptor/annihilator chromophores and materials. TF processes will be shown to
operate at high efficiencies with concomitant linear incident power density response,
demonstrated in both theory and experiment using non-coherent photons. Upconversion-based
photoaction observed in water splitting photoelectrochemical cells and operational
photovoltaics will also be discussed.
bio:
Felix (Phil) Castellano earned a B.A. in Chemistry from Clark University in 1991 and a
Ph.D. in Chemistry from Johns Hopkins University in 1996. Following an NIH Postdoctoral
Fellowship at the University of Maryland, School of Medicine, he accepted a position as
Assistant Professor at Bowling Green State University in 1998. He was promoted to
Associate Professor in 2004, to Professor in 2006, and was appointed Director of the
Center for Photochemical Sciences in 2011. In 2013, he moved his research program to North
Carolina State University where he is currently a Professor in the Department of
Chemistry. His current research focuses on metal-organic chromophore photophysics and
energy transfer, photochemical upconversion phenomena, solar fuels photocatalysis, and
excited state electron transfer processes.