Cluster Directors


Sum Tze Chien


Assoc Prof Sum Tze Chien
School of Physical & Mathematical Sciences

Cluster Director
Renewables & Low Carbon Generation (Solar)
Energy Research Institute @ NTU (ERI@N)

(+65) 6316 2971
Office: SPMS-PAP-03-05

Tze Chien Sum is an Associate Professor in the Division of Physics and Applied Physics (PAP), School of Physical and Mathematical Sciences (SPMS), Nanyang Technological University (NTU), where he leads the Femtosecond Dynamics Laboratory. He received his Ph.D. in Physics from the National University of Singapore (NUS) in 2005. His present research focuses on investigating light–matter interactions and energy and charge transfer mechanisms and probing carrier and quasi-particle dynamics in a broad range of emergent nanoscale and light harvesting systems. Prof. Sum has published 158 papers in peer reviewed journals. His publications have received ~5044 (Scopus) citations and his H-index is 34 (Scopus).

In June 2005, he joined the Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University as a Lecturer where he switched his research field from applied nuclear physics (proton beam writing and accelerator-based nuclear spectroscopy) to Femtosecond Laser Spectroscopy and its applications. Subsequently, he set up the Femtosecond Dynamics Laboratory (xC-Lab) and the Organic Electronics Laboratory; and established a new research group at the Division of Physics & Applied Physics. He was promoted to Assistant Professor (tenure tracked) in 2008 and was subsequently promoted to Associate Professor with Tenure in Sep 2014.

He is interested in the development and application of time-resolved and time-integrated optical spectroscopic techniques to interrogate the fundamental and applied properties of materials – i.e. probing the energy and charge transfer mechanisms in semiconducting nano-heterostructures & light harvesting systems; as well as investigating the nonlinear optical properties of nano-scale systems.


Research Interests

My current research focuses on investigating light matter interactions; energy and charge transfer mechanisms; and probing carrier and quasi-particle dynamics in a broad range of emergent nanoscale light emitting and light harvesting systems using Femtosecond time-resolved spectroscopy. These can be categorized under two main research themes: (i) nanophotonics and lasing and (ii) photovoltaics. Specifically, I seek to address the following three questions in these systems:

  1. Where did the energy go? That is the interplay of carrier/quasi-particle dynamics between the host energy levels, defect energy levels and the dopant energy levels.

  2. What are the underlying photo-physics and light-matter interactions that give this system its unique characteristics? That is the various processes such as carrier-carrier scattering, carrier-phonon scattering, radiative recombination and auger recombination etc.

  3. How can these properties/technologies be improved for practical applications? That is how the knowledge gained be used for the development of novel optoelectronic devices; nanolasers; and photovoltaic devices.