Research | The Domke Group

The organization of water in proton or anion exchange membranes determines to a large extent the performance of fuel cells, affecting both ion transport and catalytic efficiency. Thus, establishing the molecular properties, such as spatial arrangement and chemical interactions, of water in fuel cell membranes provides a physico-chemical basis for an improved understanding of device performance. With help of coherent anti-Stokes Raman spectroscopy (CARS), we want to quantify the water content inside the membrane and visualize its distribution in 3D with (sub)micrometer resolution. The high sensitivity of CARS provides millisecond temporal resolution and thus allows us to directly monitor how membrane flooding and dehydration processes proceed. _{Correlated interfacial water transport and protonconductivity in perfluorosulfonic acid membranes
X. Ling, M. Bonn, S.H. Parekh, K.F. Domke*
Proceedings of the National Academy of Sciences 2019, 116, 8715-8720. Nanoscale distribution of sulfonic acid groups determines structure and binding of water in Nafion membranes
X. Ling, M. Bonn, S.H. Parekh*, K.F. Domke*
Angewandte Chemie International Edition 2016, 55, 4011-4015.}

In view of depleting fossil energy resources, the development of cheap and flexible alternative energy conversion concepts is vital. Photovoltaic materials, like dye- or quantum-dot sensitized surfaces, or perovskites, that transform sunlight into electricity are a prime example of such alternative concepts. To improve solar cell devices and further the technology toward large-scale application, molecular-scale insight into the physico-chemical properties of the complex sensitizer/electrode/electrolyte system is required. Our research aims to shed light on solar cell interfacial processes on the nanoscale under operando conditions to help answer key questions in solar cell development: What is the nature of sensitizer-electrode-electrolyte interactions and their relation to surface morphology? Can device activity be controlled through the presence of defect sites and performance-enhancing molecules or particles? What is the chemical origin of device degradation upon UV irradiation and/or in the presence of oxygen or water? Correlating known macroscopic device behaviour to molecular-level processes under realistic working conditions enables performance evaluation of solar cell surfaces in an unprecedented detailed manner and paves the way for rational device design. _{The SERS signature of PbS quantum dot oxidation
K. Stadelmann, A. Elizabeth, N. Martín Sabanés, K.F. Domke*
Vibrational Spectroscopy 2017, 91, 157-162.}