Job descriptionAre you eager to work as an experimental photophysicist on unraveling the mechanisms that limit the efficiency of displays and other applications of organic light-emitting diodes (OLEDs)? In this PhD project, you will experimentally study the interaction of the excited organic molecules in OLEDs with charges and with other excited molecules. Your work will provide the experimental validation of novel theoretical and advanced simulation methods that are developed by two other PhD students. The breakthroughs that you develop, in this team, will advance our fundamental understanding of the functioning of OLEDs and will allow industry to increase the efficiency and lifetime.
The projectIn OLEDs, an electrical current through an organic layer structure leads to the formation of electron-hole pairs ('excitons') that can decay radiatively. The efficiency with which this light-emission process occurs can be very large when the current density is small. However, at large current densities the excitons can be lost due to an interaction with a hole or an electron ('quenching'). Also exciton-exciton interactions, leading to the loss of an exciton, can then become strong. These two important loss processes are so far only understood in an empirical and phenomenological way. In the project 'SEQUIOA' (Suppressing Exciton Quenching in OLEDs: an Integrated Approach) we aim at developing an experimentally validated simulation tool that enables carrying out predictive molecular-scale calculations of exciton quenching. This project of three PhD students is a collaboration between the group Molecular Materials and Nanosystems (M2N) of the Applied Physics and Science Education Department of the TU/e (experiment and theory,
https://www.m2ngroup.nl/) and the group Theoretical Chemistry in the Faculty of Science of the Vrije Universiteit of Amsterdam (VU-A). The project is supported by world‑leading companies on the development of advanced functional materials (Merck, Germany) and on advanced simulation software tools (SCM and Simbeyond, The Netherlands).
The experimental project at TU/e will be carried out under the supervision of
prof. dr. Reinder Coehoorn in the M2N group, in collaboration with
prof. dr. Peter Bobbert in the M2N group, who supervises the theory part of the project. The group has an extensive experimental infrastructure for photophysical experiments on thin films and devices, enabling carrying out time-resolved photoluminescence studies and studies that probe the electronic structure, such as ultraviolet photoelectron spectroscopy (UPS). The group has a vast experience on the development and application of Monte Carlo simulations, which in a collaboration with VU-A will be further developed so that the simulations provide molecule-specific predictions. The company Merck will provide state-of-the-art OLED materials and devices.