* Director Center for Superfunctional Materials (CSM), UNIST (2014–present) 
* Distinguished Professor of Dept. of Chemistry, UNIST (2014–present)
* Director of CSM, Pohang University of science and Technology POSTECH (1997-2014)
* Professor of Dept. of Chemistry at Pohang University of Science & Technology POSTECH (1988-2014)
* Visiting Scholar, Dept. Elect. Engineering & Nano Center, Columbia University (2004-2005)
* Visiting Scientist/Professor, Dept. of physics, MIT (1994-1995)
* Visiting Assistant Professor, Researcher Assistant Professor, Rutgers University (1985-1987)
* Postdoctoral Researcher Fellow, IBM (1982-1985)
* Instructor, Assistant professor, Dept. of Physics Chungnam National University. (1975-1978)