Stefan Meskers is Associate Professor at the Molecular Materials and Nanosystems group. He studied at Leiden University and obtained his PhD there in 1997 on spectroscopy with circularly polarized light to probe binding of small chiral molecules to proteins. As postdoc at Marburg University, he became deeply interested in the optical properties of molecular semiconductors and organic electronics. In 2001 he joined Eindhoven University of Technology with the help of a postdoctoral fellowship from the Royal Dutch Academy of Sciences. Since then he has been using optical spectroscopic methods and (circular) polarization spectroscopy to investigate charge generation and recombination in organic semiconductors, with the aim of making solar cells and photodetectors. Further research has focused on plastic electronic memory cells. Most recently we started studying the fundamental role of the quantum of electromagnetic energy in molecular materials, i.e. the ‘polariton’, in the interaction of these organic semiconductors with light.