Master projects

The M2N group welcomes Master students from Chemical Engineering and Chemistry, Applied Physics, and Sustainable Energy Technology at the TU/e to perform their graduation projects. For general information on our research program and possible topics for your graduation project, please contact René Janssen. Some examples of current openings for projects are provided on this page, but we will be happy to discuss other options with you to tailor your project to your wishes and talents. On our research page you can get an impression of the various research topics and projects that we address within M2N.

Redox flow batteries
Non‐aqueous organic redox flow batteries from abundant all‐carbon based materials can provide a sustainable solution for massive energy storage in the future. However, organic molecules that are capable of highly reversible redox chemistry and possess prolonged solution stability in their charged state are scarce. The ultimate goal of this project is a detailed understanding on structure‐property relations of redox active molecules and developing materials that can be used for large‐scale energy storage. You will be investigating new anolyte and catholyte molecules that are expected to meet the stringent requirements for this type of energy storage using an interdisciplinary approach, combining organic synthesis, electrochemistry and application in prototype redox flow batteries.
For more information contact: Nicolas Daub or René Janssen

Dion‐Jacobson layered perovskite solar cells
Reducing the dimensionality of perovskites from 3D to 2D is a promising approach to enhance the stability of perovskite solar cells, while maintaining high efficiency. Recently, significant developments in the Dion‐Jacobson (DJ) 2D perovskite phase have brought the efficiency of such solar cells to almost 18%, demonstrating the high potential of DJ perovskites for highly efficient and stable solar cells. Your research project will focus on the fabrication of efficient solar cell devices with Dion‐Jacobson perovskites. DJ perovskites possess a peculiar crystal structure, with a diammonium organic cation acting as a spacer between lead iodide octahedra . In this project, you will work on several deposition and characterization techniques (UV‐vis, PL, XRD, GIWAXS, SEM) to make solar cells and characterize the perovskite phase. Several devices configurations and organic cations will be explored. The goal of the project is to make solar cells with different device configurations (pure DJ perovskites or 2D/3D devices), to characterize the DJ phase, and to achieve high efficiency devices by carefully changing deposition techniques and organic cations.
For more information contact: Alessandro Caiazzo or René Janssen

Understanding interfacial traps & recombination processes
The interfaces of perovskite solar cells are defect‐rich in nature. The interplay between these interfaces and the charge transport layer has a significant impact on loss processes resulting in lower device efficiency. By systematically varying the doping level of the transport layer we can better understand the effect of interfacial recombination processes. In this project we will dope the PC60BM charge transport layer with a compound to form radical anions. Based on the doping degree a loss of open circuit voltage is observed, which is partially reversible with light soaking. This (reversible) loss of Voc will be related to interfacial trap states present in the perovskite layer and how they interact with the (doped) charge transport layer.
For more information contact: Bas van Gorkom or René Janssen

Proximity orbital and spin-orbit effects of WSe2 on bilayer graphene
Heterostructures of two-dimensional materials can fundamentally alter their properties due to proximity effects. For example, graphene or transition metal dichalcogenides can serve as a new platform for opto-spintronics, promoting graphene towards applications. In this project you will study the band structure of this heterostructure with microARPES, angular resolved photoemission, STM and optical techniques to measure the relevant valence electron states and in particularly the spin-orbit split states, trying to understand the electric field spin-orbit effect.
For more information contact: Kees Flipse

Organic fool’s gold
Crystals of some organic dye molecules look like gold; the molecular material reflects light with high efficiency. We use these crystals to make new types of mirrors that can be switched on or off electrically . With these novel optical switches we want to contribute to more energy‐efficient internet. In the project you synthesize a dye molecules. Grow crystals of optical quality. Measure optical and electrical properties and built your own ‘optical switch’!
For more information contact: Stefan Meskers

Scanning tunneling microscopy/spectroscopy (STM/STS) on graphene nano ribbons
In this project you will use scanning tunneling microscopy to study the morphology and local electronic structure of graphene nano ribbons, in particular the edge regions. The results will be compared with dedicated electronic structure calculations in which strain effects are also taken into account. In this way we try to understand the spin-polarized signatures of these ribbons.
For more information contact: Kees Flipse

Wide‐bandgap perovskite solar cells
Wide bandgap perovskites are likely to play an important role in the next generation of multi‐junction solar cells, where multiple solar cells (silicon or perovskite) are combined to achieve high efficiency devices. Wide bandgap perovskites, however, suffer from high voltage losses, which limit device efficiency. Your research project will focus on the fabrication of efficient wide‐bandgap perovskite solar cell devices, with a focus on the reduction of voltage losses. Such losses can be reduced by using a two‐dimensional perovskite interlayer or additive, even though its fabrication is complex and must be optimized. In this project, you will use gain knowledge in device fabrication and characterization with a variety of techniques, such as UV‐vis, fluorescence spectroscopy, XRD, SEM, and others. The goal of the project is to make solar cells with high bandgap and high open‐circuit voltage, by using a 2D perovskite interlayer/additive, minimizing the voltage losses and paving to way to a deeper understanding of this fascinating material.
For more information contact: Alessandro Caiazzo or René Janssen

Electroluminescence in organic solar cells
Solar cells can be operated as light‐emitting diodes, giving rise to electroluminescence (EL). In organic solar cells, EL is often used to study low‐energy charge‐transfer states to find the origin of voltage losses. Due to interference of light, experimental EL spectra are influenced by the optical properties of all layers in a solar cell. To obtain meaningful information the optical stack must be considered, but this is largely neglected so far. Without taking the environment into account, information extracted from EL is not correct. We need to correct the EL spectrum for these effects to properly characterize the low‐energy states in state‐of‐the‐art organic solar cells and find the origin of voltage losses. To extract all information hidden in the low‐energy EL spectra of organic solar cells we will experimentally study and model the effect of interference of light. The project encompasses fabricating and characterizing organic solar cells with different stack configurations, measuring and analyzing the electroluminescence spectra, correcting for the optical environment, and then extracting the intrinsic electroluminescence spectra.
For more information contact: Tom van der Pol or René Janssen

Gradient doping of charge transport layers for perovskite solar cells
Charge transport layers play a vital role in solar cells, as they are responsible for charge extraction from the absorber layer and consequent conduction to the electrodes. Typically, these layers are doped to increase their conductivity, though this often comes at the cost of charge selectivity or an increase in interfacial recombination. Here, we wish to apply a doping gradient to the charge transport layer by co‐evaporation of the dopant and charge transport layer. This way, a small undoped layer can be used at the interface with the absorber, allowing for charge selective extraction. On top of the undoped layer a gradient doped transport layer is deposited, which in turn facilitates efficient charge transport. The project will involve the fabrication of charge transport layers with a doping gradient using a co‐evaporation process and characterization via UV‐vis-NIR spectroscopy, conductivity, and current-voltage characteristics. In the second phase these doped transport layers will be applied in perovskite solar cells and the fully characterized.
For more information contact: Bas van Gorkom or René Janssen

Single crystal perovskite solar cells
Polycrystalline perovskite films have been successfully used to prepare efficient solar cells. However, grain boundaries that are abundant in such thin films and such sites introduce electronic defects that can impede solar cell performance. This project would aim to develop a single‐crystal perovskite solar cell to overcome grain boundary‐related performance losses. The project would start with the fabrication of iodide‐based perovskite crystals and then proceed to develop such structures on charge selective surfaces as a route to fabricate efficient solar cells. Finally, multijunction‐compatible wide‐bandgap perovskite solar cells would be prepared as a proof‐of‐concept device. The project would gives an opportunity to design creative experiments around the fabrication of single crystals and the characterization using structural and spectroscopic techniques. The goal of the project is to make single crystal perovskite solar cells as opposed to polycrystalline thin films in order to reduce non‐radiative recombination and improve efficiency. A wide‐bandgap proof‐of‐concept would be developed for eventual multijunction integration.
For more information contact: Kunal Datta or René Janssen

Distributed Bragg reflectors for transparent organic solar cells
Distributed Bragg reflectors (DBRs) consist of a multilayer stack of materials with different refractive indices. DBRs can be tuned to create wavelength‐selective mirrors and are used in transparent organic solar cells to improve transmittance in the visible region and simultaneously increase absorbance in UV and near infrared to enhance efficiency. The goal of this project is to fabricate a DBR for incorporation in a semi‐transparent organic solar cell to enhance either efficiency or aesthetics. Optical modeling plays an important role in DBR development. You will work with and improve modeling software based on Matlab or Python. Multilayers of different materials will be fabricated using methods such as evaporation, spin‐coating, sputtering etc. Having obtained control over the reflectivity of the multi‐layer stack. It becomes possible to incorporate this stack in a semi‐transparent solar cell.
For more information contact: Tom van der Pol or René Janssen

High efficiency perovskite solar cells
Within only a decade, perovskite solar cells have improved their efficiency to more than 25%. This technology is rapidly becoming a comparable alternative to the most common silicon solar cells. However, stability issues still need to be tackled before perovskite solar cells can be commercialized: one possibility to improve both stability and efficiency is to use 2D perovskites interlayers or additives. Your research project will focus on the fabrication of efficient solar cell devices with 2D perovskites interlayers and additives: a variety of perovskite layers (mixed cations or formamidinium‐based) and interlayers/additives will be synthesized and used. In this project, you will use gain knowledge in making solar cells and characterizing them via current-voltage measurements, UV‐vis-NIR spectroscopy, fluorescence spectroscopy, XRD, SEM, (sub‐bandgap)EQE. The goal of the project is to make high efficiency solar cells by optimizing our current device structures and understanding the underlying mechanisms responsible for the enhancement of solar cell performances via 2D interlayers / additives.
For more information contact: Alessandro Caiazzo or René Janssen