Date : 30 May 2017 (Tuesday)
Time : 2.30 pm – 4.30 pm
Venue : Meeting Room, N31, Centre for Sustainable Nanomaterials (CSNano), Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Skudai, Johor Bahru [google map]
Tak W. Kee is a Assoc. Professor of Chemistry at School of Physical Sciences, Department of Chemistry, University of Adelaide, Australia. He received his Ph.D. in Chemistry at the University of Texas in 2003. He have experience in the development and/or applications of multipulse-excitation femtosecond spectroscopy, coherent broadband two-dimensional electronic spectroscopy, coherent anti-Stokes Raman scattering microscopy, two-photon fluorescence, second harmonic generation microscopy. His current research is focused on using multipulse-excitation femtosecond laser spectroscopy and coherent broadband two-dimensional electronic spectroscopy to investigate and understand dynamics of energy migration and charge carriergeneration in organic photovoltaic materials.
“Fluorescence, Electroluminescence and Excited-State Photophysics of Conjugated Polymer Nanoparticles”
By Assoc. Prof. Dr. Tak W. Kee
Conjugated polymer nanostructures are attracting significant interests owing to their applications in light emitting devices, fluorescence imaging and organic photovoltaics. Conjugated polymer nanoparticles offer colloidal stability in aqueous solution, good photostability, and tunable luminescence properties. First, the applications of conjugated polymer nanoparticles as fluorescence labels in cell imaging and as emitting species in organic light emitting diodes will be presented. In addition, the use of pump−push−probe spectroscopy, an incoherent multipulse femtosecond spectroscopic technique, to study the early-time dynamics of the high-energy excited states of poly(3-hexylthiophene), P3HT, will be discussed. The dynamics of these high-energy excited states are closely related to the photovoltaic effect of P3HT. The results show that most of the high-energy excited states undergo rapid relaxation to the lowest-lying singlet excited state due to ultrafast torsional motions of P3HT. Approximately 11% of the high-energy excited states dissociate to form charge carriers, which in turn undergo geminate recombination to produce ground-state P3HT. In short, this study has reveal insight into the photovoltaic effect of P3HT.