The M2N group welcomes Bachelor students from Chemical Engineering and Chemistry and Applied Physics at the TU/e to perform their final project. For general information on our research program and possible topics for your final BSc project, please contact René Janssen. Some examples of specific projects are provided on this page, but we will be happy to discuss other options with you to tailor your project to your interest and talents. The main research topics and that we address within M2N are.
Monte Carlo simulations. Contact: Reinder Coehoorn or Peter Bobbert
Pulsed photoluminescence experiments. Contact: Reinder Coehoorn
Models for hopping transport in organic semiconductors. Contact: Peter Bobbert
Magnetic force microscopy on hydrogenated graphene. Contact: Kees Flipse
Ballistic/hydrodynamic transport experiments. Contact: Kees Flipse
Raman spectroscopy experimental/theory. Contact: Kees Flipse
Organic solar cells
New organic semiconductors for solar cells. Contact: René Janssen
Energy levels vs. open-circuit voltage. Contact: René Janssen
Design new tandem and triple junctions by optical modelling. Contact: René Janssen
Perovskite solar cells
New perovskite semiconductors for solar cells. Contact: René Janssen
Time-resolved electroluminescence. Contact: Stefan Meskers
Tandem and triple junction perovskite solar cells. Contact: René Janssen
Organic Flow Batteries
New amphoteric redox active molecules. Contact: René Janssen
Polaritons in Organic Crystals
Reflection of molecular crystals. Contact: Stefan Meskers
Catalysts for photo-electrochemical water splitting andCO2 reduction. Contact: René Janssen
Examples of current projects for bachelor students of Applied Physics and Chemical Engineering & Chemistry are:
Time-resolved electroluminescence of wide band gap perovskites
Thin film metal halide perovskite solar cells are attracting enormous attention. Efficiencies are high, but to reach the thermodynamic limit of solar energy conversion, important challenges must be overcome. One is understanding and controlling defects. By studying the electroluminescence of these solar cells we can gain these insights. In electroluminescent mode, a short burst of light is observed after the driving voltage has been switched off. This “overshoot” is related to trapped charges. We have previously identified the overshoot for small bandgap (~ 1.6 eV) perovskites. In this Bachelor project you will study the effect for wide band gap (< 1.7 – 2.0 eV) perovskites. The work will involve measuring the time-resolved electroluminescence of perovskite solar cells under different conditions, analyzing the results, and developing models that can explain the results.
Contact: Stefan Meskers
Gradient doped hole-transport layers for perovskite solar cells
Lead halide perovskites can now be used to make very efficient (25%) photovoltaic cells. One of the crucial issues to be understood and solved is the loss in energy between the bandgap and the open-circuit voltage of the solar cells. We want to understand the role of the hole extracting contact. You will test the effect of a vertical gradient in the p-type doping of hole-transport layers on the performance of perovskite solar cells. Gradient doping can be accomplished by co-evaporating of an organic hole-transport layers and a suitable dopant. In this Bachelor project you will investigate the extent of doping and conductivity of the resulting layer as well its performance in perovskite solar cells. The work will involve fabricating these layers using thermal evaporation in high vacuum, optical absorption spectroscopy, and making and characterizing solar cells.
Contact: Bas van Gorkom & René Janssen
Low-cost, sensitive perovskite X-Ray detectors for medical imaging
Metal halide perovskites are mainly known in the field of solar cells. Together with Holst Centre, we are tuning perovskites also for other applications. The high charge carrier mobility (μ) and lifetime (τ) product, their high stopping power combined with low material and manufacturing costs makes perovskites a promising radiation detection material for X- and g-rays. In case of X-ray detectors, the use of perovskites could lead to improved image quality, which can be translated into significantly lower exposure levels for medical or security screening of humans. Highest μτ products are reported for high-quality single crystals. This method is however difficult to scale to large area cost-effectively. In this Bachelor project we aim to explore printing methods to coat 1-mm-thick polycrystalline films. First experiments show promising results, however the dark current, i.e. resistivity, which among others determines the detection limit is far from optimal. In this project you will study how the μτ product and resistivity depend on the material composition, film crystallinity, the preparation parameters and electrode contact materials. Thick films will be deposited at Holst Centre. Electrical characterization will be carried out at the university. In case of promising results, X-ray characterization will be performed by Holst Centre’s partners Philips and Siemens.
Contact: Gerwin Gelinck
Organic photodetectors with improved sensitivity in the near-infrared
Organic bulk heterojunction photodetectors can now be used to make very sensitive visible light detectors. Looking further, TU/e, Holst Centre and its industrial partners aim to develop organic photodetectors with high sensitivity in the near-infrared region. This implies the use of low-bandgap electron donor polymer and non-fullerene acceptors. The reduced injection barriers of the organic materials with the electrodes also implies the use of thin electron or hole blocking layers to reduce undesirable dark current injection. In this Bachelor project you will investigate the extent of doping and conductivity of the resulting layer as well its performance in perovskite solar cells. The work in this Bachelor project will involve fabricating these blocking layers using thermal evaporation on top of the donor-acceptor blends, making and characterizing detector devices, and establishing which charge carrier is mainly responsible for the dark current injection, the electron or the hole.
Contact: Gerwin Gelinck
Strain induced curved regions of graphene leads to hydrodynamics
Graphene grown on SiC is strained due to the mismatch of both lattices. Strain creates ripples on the graphene surface which leads to strong modifications of the electron and the phonon structure of graphene as well as the electron-phonon coupling. In this complex game between electrons and phonons a linear dependence of the resistivity versus temperature is predicted in the temperature regime of 100-600 K. In this BEP project you will study the strain effects and the electron-phonon coupling as a function of temperature. This work will involve the growth of graphene, Raman spectroscopy and some modeling.
Contact: Niels de Vries, Robbert Schoo en Kees Flipse
Testing a new cantilever design achieving atomic resolution at room temperature
In this project we investigate a surface of Rutheniumoxide (RuO2), an excellent catalyst for water splitting into hydrogen and oxygen gas, potentially enabling efficient methods for renewable energy storage. Theoretical calculations predict a magnetic moment present on the surface of RuO2. In this research we investigate if magnetism plays a significant role in the oxygen gas reaction. Therefore, we need true atomic resolution of the RuO2 surface atoms. A highly promising method is to employ non-contact atomic force microscopy (NC-AFM). With this method, a small metal tip is placed on a special, mechanical double prong AFM cantilever. We can scan the surface in an ultra-high vacuum setup and aim to acquire first time AFM based atomic resolution of RuO2 at room temperature. You will prepare and test the cantilevers on RuO2 and perform simulations to optimize the quality factor of the cantilever to increase the sensitivity.
Contact: Michael Verhage, Oleg Kurnosikov en Kees Flipse
Simulations of stability of mixed perovskites
The band gap of lead halide perovskites can be tuned by mixing halides, for example iodine and bromine. The problem is that demixing might occur, for example in an iodine-rich and a bromine-rich phase. Under illumination, the trend for this demixing may be enhanced, because photogenerated carriers and excitons will prefer to move to the low-band gap phase. This effect, known as the Hoke effect, presently impedes band gap tuning by halide mixing. In this project, you will study the demixing process by kinetic Monte Carlo (kMC) simulations of the motion of halide ions. You will try to understand and model experiments done in the group on this effect. The project will be carried out in collaboration with the Center for Computational Energy Research.
Contact: Peter Bobbert
Beyond-mean field simulations of charge & exciton dynamics in organic devices
Simulations of charge and exciton dynamics in organic devices like Organic Light Emitting Diodes (OLEDs) are presently done using kinetic Monte Carlo (kMC) simulations. However, these simulations are extremely time-consuming. An alternative is to perform simulations within a mean field framework, where the average occupation probabilities of sites by charges or excitons are calculated and correlations of these occupation probabilities between sites are neglected. Such an approach is computationally fast, but often not accurate enough. In this project you will develop a simulation approach that goes beyond mean field by taking into account two-site correlations of the occupational probabilities. Such an approach should combine the computational efficiency of a mean field approach with the accuracy of a kMC approach. The project will be carried out in collaboration with our spin-off company Simbeyond, which is interested in commercial exploitations of new simulations techniques.
Contact: Mahyar Taherpour, Reinder Coehoorn, Peter Bobbert
Beyond-mean field simulations of charge dynamics in network of dopants
Networks of dopants like boron atoms in silicon contacted by multiple electrodes can show complex electrical characteristics that can be exploited for neuromorphic computing. To understand these characteristics, simulations of the charge dynamics in these networks should be performed. Like in the above project (beyond-mean field simulations of charge & exciton dynamics in organic devices), however, kMC simulations of this charge dynamics are extremely time-consuming. Like in the above project, you will develop a fast, yet accurate, beyond-mean field approach that takes into account two-site correlations in the occupational probabilities of sites. The project will be carried out in collaboration with the NanoElectronics group at the University of Twente, where experiments on these dopants systems are done.
Contact: Peter Bobbert