Private address: Address at work:
Empa, Lab for Functional Polymers
Neunbrunnenstrasse 108b Ueberlandstrasse 129
8050 Zürich 8600 Dübendorf
phone: +41 (0)79 381 7394 phone: +41 (0)58 765 4084
Born 25.11.1961, Swiss, citizen of Zürich
Education and Emplyoment:
since 2017 Deputy editor of the journal STAM, Science and Technology of Advanced Materials.
since 2014 Associate editor of the journal STAM, Science and Technology of Advanced Materials.
April - June 2011 Sabbatical stay at the National Physical Laboratory (NPL) in London.
since 1993 Employed at Empa, scientific co-worker and assistant of head of Laboratory for Fossil Fuels,
since 2003 group leader and assistant of head of Laboratory for Functional Polymers.
1982 – 1992 Studies at University of Zürich, chemistry and physics, doctoral thesis in physical chemistry.
1968 – 1981 Primary school, high school in Zürich.
- Safety administrator of the Lab for Functional Polymers
- Responsible for the NMR research&service facility at Empa
- Group leader and assistant of head of Lab for Functional Polymers
During my master and doctoral thesis I studied photoreactions of aromatic ketones with the method of “chemically induced dynamic nuclear polarization” (CIDNP); radical reactions were initiated by a laser pulse inside an NMR spectrometer, spectra taken after short times contain information on the reaction kinetics and mechanisms. At Empa, I was responsible for several years for the “NMR service”, I am familiar with state-of-the art methods of solution and solid-state NMR. In parallel, I was involved in the characterization and chemical functionalization of biological polyesters (polyhydroxyalkanoates, PHAs). These materials are synthesized by bacteria; the basic polymer composition depends on the carbon feed, and post-chemical modification allows tuning and adjusting important physical properties. PHAs are biocompatible and biodegradable, and have potential applications in the field of drug delivery or tissue engineering.
In 2003, I joined the Laboratory for Functional Polymers. I am leading the “organic optoelectronic device group” and we have built a fully equipped laboratory for the fabrication of (organic) thin-film devices (glove-box, equipment for film coating, UV-vis and PL measurements, profilometer and AFM, cyclic voltammetry). My main research interest is on the structuring of thin organic films and the development of organic optoelectronic devices giving emphasis to organic solar cells and photodiodes. I have several years of experience with the device application of polymethine dyes, such as squaraine and cyanine dyes. Of special interest are dyes that absorb selectively in the near-infrared wavelength (NIR) region and we used such dyes for the fabrication of visibly transparent solar cells and photodiodes.
Recently, we introduced polymethine dyes for the fabrication of all-organic upconverters. The idea of any upconversion device is to integrate an infrared photodetector with a visible light-emitting diode. Such a device absorbs NIR light and emits light in the visible. Thereby, a NIR scene can be converted into a visible picture that can be captured by a conventional camera. We developed organic upconverters with a peak sensitivity at 1 μm and fabricated multilayer upconverters entirely from solution.
We also use polymethine dyes (and polymers) for the fabrication of light-emitting electrochemical cells (OLECs). The functional principle of OLECs relies on the presence of mobile ions, and because our “workhorse” cyanine dyes are actually organic salts these required ions are inherently already present and no external salt has to be added. In a first work we investigated the general working principle of cyanine-OLECs and tried then to improve the performance by using visible emitting cyanine-cyanine host/guest systems. We developed a generic method to determine the position of the intrinsic junction in sandwich OLECs where light-emission occurs. Together with capacitance or photoluminescence quenching experiments – that yield the width of the intrinsic junction – the development of the p-doped/intrinsic/n-doped device situation can now be tracked as a function of time. In the meantime we used in addition angular emission spectra to determine the shape and position of the emission zone. Using capacitance and Stark effect measurements on operated LECs we could show that there indeed exists a doping – and consequently ion – gradient towards the intrinsic zone. We found for state-of-the art polymer OLECs that a slightly lowered salt concentration and layer thickness result in a substantial efficiency increase. We developed a comprehensive optical modeling study that includes the doping-induced changes of the refractive indices and self-absorption losses due the emission-absorption overlap of intrinsic and doped polymers.