Investigation of efficient next-generation photo-electrochemical devices

Dr Christoph Schnedermann
Research Fellow 2018

Dr Christoph Schnedermann
University of Cambridge

Solar energy is the most abundant energy source available to us to meet the world’s rapidly increasing energy demands in a sustainable manner. Drawing inspiration from photosynthesis, scientists around the world are seeking efficient ways to generate ‘Solar Fuels’, by efficiently harvesting sunlight and storing it in readily accessible and grid-compatible alternative fuels with the aim to replace oil and gas. One way to achieve this task is by bringing a photovoltaic element in contact with an electrochemical catalyst. Here, the photovoltaic element harvests sunlight by converting it into electricity, which is then used by the catalyst to power electrochemical reactions like water splitting into oxygen and the solar fuel hydrogen.

Currently available devices that make use of this concept are based on conventional semiconductor photovoltaics, like silicon or gallium arsenide. These materials suffer, however, from limitations of cost, lack of mechanical flexibility and lack of electronic tunability. Promisingly, recent research has developed significantly cheaper and more versatile materials which are already competing with silicon in terms of efficiency and may soon overcome it. These new materials offer an exciting avenue towards highly efficient and flexible solar energy storage, if combined with the appropriate electrochemical catalysts. It is, however, not clear if and how ‘conventional’ design rules for electrochemical catalysts and devices apply to such new materials.

"it is imperative for us to understand how to best interface novel photovoltaic materials with suitable electrochemical catalysts to firmly establish a globally sustainable energy infrastructure"

To guide the design of such devices, it is imperative for us to understand how to best interface these new materials with suitable electrochemical catalysts. My project will investigate potential device architectures and focus on understanding the interface-interaction between such new photovoltaic materials and electrochemical catalysts after exposure to light. To this end I will design and use experimental techniques that will allow me to directly follow the underlying physical processes occurring at the interface on femtosecond timescales and with nanometre precision. Crucially, the project will identify efficiency bottlenecks in these designs and provide valuable guidelines for their improvement, ultimately leading to establishing the future of a flexible and sustainable energy society based on solar energy.