University of Southern Denmark

Photovoltaics and battery materials form the basis of the research conducted by the two SMART Project PhD students hosted at the University of Southern Denmark. Discover more about the students and their research on this page.

X-ray and neutron scattering studies metal oxide interlayers for photovoltaic applications - Mariam Ahmad

Mariam is a first year PhD student with Prof. Morten Madsen at the Organic Solar Cells group at SDU NanoSYD. She is originally from Copenhagen, where she obtained her bachelor and master degrees in Nanoscience at UCPH. She moved to Sønderborg in December 2019 to begin her PhD at SDU.

Organic solar cells (OSCs) have recently gained a lot of popularity due to their light weight, mechanical flexibility, non-toxic materials, low cost manufacturing and compatibility with scalable printing techniques, which makes them a cheaper and more sustainable alternative to their inorganic Si-based counterparts. The first OSCs struggled with low power conversion efficiencies (PCEs), which made them undesirable for widespread commercialization, but recently OSCs based on non-fullerene acceptors have reached PCE values above 18%, meaning that commercialization can soon become a reality.  In organic solar cells, the organic photoactive layer is sandwiched between two electrodes: an anode and a cathode. These electrodes are usually made from a metal or a transparent conductive oxide. One of the four processes that determine the efficiency of an OSC is charge collection at the electrodes. This process is inefficient when the organic materials of the active layer are in direct contact with the electrodes, because the electrode materials give rise to a high charge injection energy barrier at the organic/electrode interface, which causes charges to gather at the interface and not reach the electrodes. This challenge can be overcome by incorporating some interlayers between the active layer and the electrodes that lower this energy barrier. Metal oxide thin films have proven to be perfect for this purpose thanks to their suitable electronic structure. When metal oxides are implemented as charge contacts in OSCs, they lower the charge injection barrier between the active layer materials and the electrodes thanks to a favorable energy level alignment at the metal oxide/organic interface. Metal oxides are charge selective and can be used as either hole transport layers (HTLs) or electron transport layers (ETLs). The use of metal oxides as charge transport layers has proven to increase both device performance and stability of OSCs. These metal oxides are the focus of this PhD project. The main objective of this project is to use various X-ray and neutron scattering techniques to study the composition, structure and electronic properties of these metal oxides and their interfaces with organic active layer materials to understand their role in OSCs.

Preparation and investigation of selected cathode materials using operando neutron and X-ray diffraction techniques - Andreas Østergaard Drejer

Andreas completed his BSc in Chemistry at University of Southern Denmark (SDU) in 2017. During his bachelor studies he worked on several projects involving synthesis and characterization of different functional inorganic materials. In 2019 Andreas started his PhD position under supervision of Assoc. Prof. Dorthe B. Ravnsbæk at SDU and in collaboration with Haldor Topsøe A/S. In his PhD project, Andreas investigates electrode materials for Li-ion and Na-ion batteries, such as transition metal (TM) oxides of the layered NaxTMO2-type. In his project he employs a wide range of characterization techniques with the main focus on electrochemical analysis, and X-ray and neutron scattering methods. These methods are also used in combination to elucidate structural transformation in the materials under operational conditions (e.g. galvanostatic battery charge/discharge) as this is very important for the understanding on how to develop new or improve already existing electrode materials. For this purpose, a new electrochemical operando cell for neutron diffraction is currently under development.