Achieving high current densities while maintaining a high energy conversion efficiency is one of the main challenges for enhancing the economic competitiveness of solar fuel producing photo-electrochemical devices [1]. I will discuss two device implementations utilizing concentrated irradiation to achieve high current density operation. The water-splitting device is utilizing thermal integration to sustain high performance while dealing with high current density and the corresponding overpotentials [2]. I will quantify the theoretical increase in the maximum efficiencies at given current densities of photoelectrochemical devices resulting from thermal synergies. I will then discuss device implementation of such an approach and show how more realistic device models (multi-dimensional, multi-scale, multi-physics) can be used to support the device implementation and its operational understanding [3]. I will then show how the design principles developed for water splitting can be translated to CO₂ reduction devices and discuss a corresponding device implementation.

[1] M. Dumortier, S. Tembhurne, S. Haussener, Energy Environmental Science, 8: 3614-3628, 2015.

[2] S. Tembhurne, F. Nandjou, S. Haussener, Nature Energy, 4: 399-407, 2019.

[3] S. Tembhurne, S. Haussener, Journal of The Electrochemical Society, 163: H1008-H1018, 2016.