Devices based on semiconducting polymers benefit from a large variety of chemical structures and can be deposited using low-cost, solution-based deposition techniques. In a proof of concept study, we have developed a low-cost, miniature spectro-photometer which is for example able to remotely detect water, based on its near-infrared transmission. Besides printed, polymer based photodetectors, we also develop and optimize polymer-based solar cells, light emitting diodes and transistors. The picture refers to our study by Tang et al. published in Advanced Materials (DOI: 10.1002/adma.201702184).

Dielectric mirrors or distributed Bragg reflectors are high-quality mirrors with superior reflectivities up to 99.9%. They are ideal to combine with strongly emitting or absorbing organic materials to create microcavities. These allow for fundamental research on strong light-matter coupling, Bose-Einstein condensation and other quantum effects. Beyond that, applications of dielectric mirrors range from hot mirrors, to narrowband sensors and lasers. We fabricate the mirrors via e-beam deposition which is highly compatible with the deposition of organic semiconductors.

Complementary to our experimental work, we apply computational techniques to model processes on the molecular scale, such as the absorption and luminescence of molecules, aggregates and blends. This is combined with optical simulations and electrical drift-diffusion simulations on the device scale to understand and optimize charge injection/extraction, transport and recombination processes in organic opto-electronic devices consisting of multiple functional layers with a typical total thickness of about 100 nm. The simulation shown above represents the optical field distribution in an organic solar cell being optimized to trap a maximum of light in the active layer. The subsequent carrier distribution, given by the balance between dynamic processes of generated carriers is critical to determine the device performance. Similar types of simulations are also used to design and optimize organic light emitting diodes for which the spectrum and outcoupling efficiency of the emitted light is affected by thin film interference effects and the position of the recombination zone.