The main research directions are on electrical and optical properties of organic semiconductors and hybrids, their relation to morphology, properties of multifunctional blends and bio-electronics. He co-authored over 370 papers in these research fields (h-index 87). He was co-recipient of the EU Descartes Prize 2003 for the development of polymer light-emitting diodes and received in 2015 the Holst Medal, awarded once every 4 years by the Dutch Royal Academy of Science, for his contribution to organic electronics.