Subsequent projects

Dr. Ursula Wurstbauer
Technical University of Munich
Walter Schottky Institut - Holleitner Group

Dr. Joel Ager
Lawrence Berkeley National Laboratory
Joint Center for Artificial Photosynthesis

2D Layered Nanosystems for Solar Hydrogen Production

In this project, we would like to follow the path towards the design of an on-chip electrochemical cell for efficient solar hydrogen production in nanoscopic photochemical devices made out of 2D materials and their heterostructures.

We therefore develop a universal platform for the electrochemical and photochemical characterisation of nanostructured 2D materials such as MoS2 in various electrolytes with high sensitivity and high lateral resolution with respect to the edge sites vs basal planes of the 2D materials. The cell design facilitates photo-catalytic investigations with the possibility to in-situ monitor the change in the optical response by photoluminescence and Raman measurements that provide insights to modified charge carrier density by molecular doping, formation of lattice defects, and impact of different electrolytes on the excitonic properties.

Precisely tailored nano-holes and -ribbons with a high edge to bulk ratio will be produced by milling with a helium ion beam facilitating sub-10 nm structure size to quantitatively study the catalytic activity of bulk, edge and defects sites. The photo-activity will be enhanced by introducing van der Waals heterostructures.


Primary project: 2D Layered nanosystems for Solar Hydrogen Production


Final Report

In the first period of the project, µ-Raman spectroscopy was successfully applied on mono- and few-layer MoS2 to study the impact of environment, e.g. on the charge carrier density [1] and to explore the photocatalytic stability of the atomistic thin membranes [2]. Such studies are of great interest, since it is predicted that transition metal dichalcogenides such as Mos2 feature high potential for application in solar hydrogen production.

In the course of the second project phase, it could be demonstrated that mono-, bi-, and few-layered MoS2 is catalytically active in the hydrogen evolution reaction (HER) [3]. In particular, the investigated transition-metal dichalcogenides show an onset-potential which depends on the number of layers. This observation suggests that the electron hopping transport across the layers dominates the reaction. Moreover, it could be verified that in mechanically exfoliated samples, the HER-activity scales with their area and in turn, with the number of defects in the basal plane.

Another focus of the project was to characterize the dielectric properties of the van-der-Waals materials in a quantitative way. To this end, the imaging spectroscopic ellipsometry was introduced to mono-layered transition-metal dichalcogenides [4]. Particularly, the excitonic transitions but also the quasi-particle band gap can be spatially resolved and characterized [5].

In the scope of the project, it was further demonstrated that the electric contact morphology in optoelectronic and photovoltaic circuits can be manipulated and influenced by a focused laser. This local annealing technique allows to manipulate both the work function and the corresponding electric fields at the metal contacts as well as the physical process, which dominate the optoelectronic response of the two-dimensional materials and circuits [6].

The great success of the project is substantiated by six publications in high impact journals, and it is the result of intense interaction between the project partners together with an on-site visit of Dr. Ager at WSI, a visit of Prof. Holleitner at the JCAP and a research stay of several weeks of MSc Eric Parzinger (PhD candidate) at JCAP.


[1] B. Miller, E. Parzinger, A. Vernickel, A. Holleitner, and U. Wurstbauer, Photogating of mono- and few-layer MoS2, Appl. Phys. Lett. 106, 122103 (2015).

[2] E. Parzinger, B. Miller, B. Blaschke, J. A. Garrido, J. W. Ager, A. Holleitner, and U. Wurstbauer, Photocatalytic Stability of Single- and Few-Layer MoS2, ACS Nano, 9(11), 11302 - 11309 (2015).

[3] Hydrogen evolution activity of individual mono-, bi-, and few-layer MoS2towards photocatalysis,  E. Parzinger, E. Mitterreiter, M. Stelzer, F. Kreupl, J. W. Ager, A.W. Holleitner, U. Wurstbauer, Applied Materials Today 8, 132-140 (2017). (2017).

[4] Imaging spectroscopic ellipsometry of MoS2, S. Funke, B. Miller, E. Parzinger, P. Thiesen, A.W. Holleitner, U. Wurstbauer, J. Phys.: Condens. Matter 28, 385301 (2016).

[5] Light–matter interaction in transition metal dichalcogenides and their heterostructures, U. Wurstbauer, B. Miller, E. Parzinger, A.W. Holleitner, J. Phys. D: Appl. Phys. 50 (2017).

[6] Contact morphology and revisited photocurrent dynamics in monolayer MoS2, E. Parzinger, M. Hetzl, U. Wurstbauer, A.W. Holleitner, Nature 2D Materials and Applications 1, 40 (2017).


Privacy Notice