KSC SEMINARS
Date & Time: Thursday 27th April, 2017 at 10am
Venue: Building 5, level 5, room 5209
Light refreshments will be provided.
Abstract: Organic and hybrid thin film electronic devices, such as memory diodes, solar cells and transistors, typically contain a functional layer based on a blend of multiple polymeric or small-molecular species whose properties cooperatively give rise to a specific function. Depending on the desired functionality, phase separation during film processing is either encouraged or suppressed. As usually at least one blend component is polymeric, mutual segmental repulsion readily overcomes the entropic driving force to form stable mixtures. For this reason, it is often observed that during solution-casting droplet-like demixed morphologies emerge due to (spontaneous) liquid-liquid (L-L) demixing. This presentation focuses on the role of this mode of phase separation in thin film electronics by presenting examples for which it is desired (memory diodes) or to be avoided (solar cells). I give an overview on the work we have done to theoretically understand and predict the influence of processing parameters, in particular evaporation, on phase domain size and composition. Where appropriate, the link between phase characteristics and device operation will be addressed, together with ways of directing L-L demixing in order to enhance morphological control.
Biography: Jasper Michels studied chemistry at the University of Amsterdam. He graduated in organic chemistry in at the group of Prof. W. N. Speckamp. He obtained his PhD degree at the University of Twente at the Supramolecular Chemistry and Technology group of Prof. D. N. Reinhoudt. After his graduation he held a post-doctoral research position (EPSRC and Marie Curie) for two years at the group of Prof. H. L. Anderson at Oxford University. He subsequently joined TNO Science and Industry in Eindhoven as a Research Scientist. In the period 2011 – 2016 Jasper has been vice-chairman of the advisory board of the Dutch Self-Healing Materials funding initiative. In September 2014 he joined the Department of Molecular Electronics of the Max Planck Institute for Polymer Research as a staff scientist. His research interests concern the overlap between soft matter dynamics and thin-film organic electronics. Using a combination of experimental and theoretical approaches his group attempts to gain profound understanding on the coupling between material properties, processing conditions, morphological features and ultimately device performance.