Project Details
Projekt
Photoelectrochemical water splitting using adapted silicon based semiconductor multi-junction cell structures
Subject Area
Physical Chemistry of Solids and Surfaces, Material Characterisation
Term
from 2012 to 2019
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 220917238
Light induced water splitting using photoelectrochemical devices without additional bias voltage has only been achieved with tandem or triple junction cells with reasonable efficiencies so far. But these devices are still limited in their performance, since they either deliver insufficient photovoltages and/or low photocurrents. Therefore, we want to explore in the present renewal project specifically designed thin film multi-junction (tandem, triple and quadruple junction) structures based on inexpensive microcrystalline/amorphous Si absorbers adapted for hydrogen and oxygen generation from water using visible sunlight. For this purpose silicon based adapted multi-junction cell structures must be prepared to provide sufficient but defined photovoltages to drive both the H2 and O2 evolution reactions. To reach high H2 yields and to minimise corrosive side reactions the atomic and electronic structure of the semiconductor surface must be modified in an appropriate way involving ultrathin passivation layers and specifically designed nano-sized metallic catalysts. Ultrahigh-vacuum based synthesis and analysis techniques as well as electrochemical characterization tools are used to clarify the involved elementary processes at the semiconductor/electrolyte interface during solar water splitting. The obtained results shall contribute to the improvement of the total efficiency of light induced H2 formation to a level, which is sufficient for technological use.
DFG Programme
Priority Programmes
Co-Investigator
Privatdozent Dr. Bernhard Kaiser
