René Janssen is full professor in chemistry and physics at the Eindhoven University of Technology (TU/e). He received his Ph.D for a thesis on electron spin resonance and quantum chemical calculations of organic radicals in single crystals. René Janssen has been visiting professor at the University of California Santa Barbara, the University of Angers, and the University of Florida. He is editor of "Organic Electronics".
The research of his group Molecular Materials and Nanosystems at the TU/e focuses on functional -conjugated molecules, macromolecules, nanostructures, and materials that may find application in advanced technological applications. Synthetic organic and polymer chemistry are combined with advanced time-resolved optical spectroscopy, electrochemistry, morphological characterization and the preparation of prototype devices to accomplish these goals. In recent years many of the activities have concentrated on organic and polymer solar cells.
Solar cells with a photoactive layer based on polymers have recently surpassed power conversion efficiencies of 10%. This important step has been accomplished by developing new, improved organic and polymer semiconductors together with advanced processing procedures. The efficiency can be further improved by using a multi-junction configuration. Compared to single junctions, multi-junction cells reduce thermalization losses by absorbing high energy photons in a wide band gap cell, and reduce transmission losses by absorbing low energy photons in a small band gap cell. Apart from increases in efficiency, the control of lifetime of the cells and high volume production technology are making very good progress.