He received his Ph.D. in 2005 from the National University of Singapore (NUS). His 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 and light harvesting systems. Dr Sum received a total of 11 teaching awards from NUS and NTU, including the coveted Nanyang Award for Excellence in Teaching in 2006 and the 2010 SPMS Teaching Excellence Honour Roll Award. Most recently, he received the 2013 SPMS Young Researcher Award; the Institute of Physics Singapore 2014 World Scientific Medal and Prize for Outstanding Physics Research; and the 2014 Nanyang Award for Research Excellence.