Giving to CREOL CREOL, The College of Optics & Photonics

Seminar: "Upconversion Nanoparticles (UCNPs): Photophysical properties and biological applications” by Kang Taek Lee

Thursday, September 27, 2018 12:00 PM to 1:00 PM
CREOL Room 103

Kang Taek Lee
Department of Chemistry
Gwangju Institute of Science and Technology (GIST)


Upconversion luminescence (UCL) is one of a few processes which increases the energy of incident photons. The mechanism of upconversion was first suggested by N. Bloembergen (1959), and experimentally revealed for the first time by F. Auzel (1966). The most popular upconverting material, NaYF4:Yb3+,Er3+, features high absorption cross section of Yb3+ (980 nm), efficient energy transfer from Yb3+ to Er3+, and well-resolved Er3+ emission in the visible range. Recently, the discovery of non-blinking and non-bleaching UCL at the single nanoparticle level accelerated various applications such as bioimaging, biosensors, and solar cells. In the first part of the talk, I wish I could convey the ideas about the current status of UCL or upconversion nanoparticles (UCNPs). In the latter part, I will present some of the recent activity of my lab at GIST: (a) single particle level measurement of UCNP, (b) distinct energy-transfer mechanism between the green and red bands, (c) stimulated emission depletion (STED) in UCNPs, (d) quantitative analysis of cellular uptake, and (e) temperature-dependent UCL intensity in perovskite crystals.


Kang Taek Lee, the associate professor of chemistry at GIST (Gwangju Institute of Science and Technology) received his BS, MS, and PhD degrees from Seoul National University (chemistry department) in 1996, 1998, and 2003, respectively. Under the supervision of Prof. Seong Keun Kim, he studied gas-phase biomolecules (amino acids, DNA and RNA bases) isolated in vacuum by jet-cooling molecular beam and lasers (nanosecond and femtosecond). He moved to the US for his postdoctoral work with X. Sunney Xie at Harvard University, where he studied single-molecule biophysics for the enzymatic turnover of beta-galactosidase (2003-2004). He also worked as a postdoctoral research associate in the group of Prof. Nobert Scherer’s at the University of Chicago (2004-2007), developing methods for FRET in large RNA molecules such as RNase P RNA. He was a senior scientist in Korea Research Institute of Chemical Technology (KRICT) (2007-2013) and joined at GIST in 2013. His research is currently focused on using upconversion nanoparticles (UCNPs) as a probe for the live cell imaging. He was honored by Hanseong Foundation as the best young chemist in S. Korea (2018). He is on a sabbatical leave to CREOL.

For additional information:

Kyu Young Han

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