Regensburg 2022 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 20: Poster

DS 20.49: Poster

Mittwoch, 7. September 2022, 16:00–18:00, P3

Development of a Transport Layer for the Integration of a TiO2-based Photoanode on a Silicon Wafer for Solar Water Splitting — •Luisa Busch, Dennis Berends, and Kai Gehrke — DLR Institut für Vernetzte Energiesysteme, Oldenburg, Germany

Recently, Segev et al. [1] proposed a three-terminal hybrid photoelectrochemical (PEC) / photovoltaic (PV) device for improved solar spectrum utilization. The concept integrates a TiO2 photoanode on an IBC silicon wafer in tandem configuration. To overcome the rather large bandgap of TiO2, which still limits the absorption of the solar spectrum and therefore the efficiency of the PEC, a sub-stochiometric TiO2 layer is advantageous. However, contacting the two semiconductors directly would result in a high recombination of the free charge carriers and thus low currents in the cell, due to band mismatch. By adding a transport layer between the two materials, for example a tunnel recombination junction, an improved current flow can be achieved. Within this work, the development of such a transport layer is presented in order to integrate a sub-stochiometric TiO2 photoanode on a Si wafer. For this purpose, the optoelectronic properties of the two semiconductor materials are characterized to select a suitable transport layer material by simulating the band alignment with AFORS-HET. Based on these results, a possible transport layer is developed and integrated into the tandem structure for electrochemical characterization.

[1] G. Segev et al., In: Nature materials, 17(12):1115-1121, 2018. doi: 10.1038/s41563-018-0198-y