%0 Conference Paper
%A Urbain, Felix
%A Smirnov, Vladimir
%A Becker, Jan Philipp
%A Rau, Uwe
%A Ziegler, Jürgen
%A Yang, Florent
%A Kaiser, Bernhard
%A Jaegermann, Wolfram
%A Finger, Friedhelm
%T Efficient multijunction thin film silicon based photocathodes for hydrogen production via photoelectrochemical water splitting
%M FZJ-2015-03193
%D 2015
%X We report on the application of multijunction thin film silicon based photocathodes for solar water splitting. Multijunction solar cells allow for high photovoltages, well above the thermodynamically required 1.23 V to drive the oxygen and hydrogen evolution reactions. However, the use of such solar cells in integrated water splitting devices imposes considerable challenges, in particular at the solar cell/electrolyte interface concerning catalysis and chemical stability. In this regard, we integrate different metal layers at the solar cell/electrolyte interface and evaluate their catalytic and stability properties.The performance of the photocathodes, with respect to photocurrent densities and onset potentials for cathodic current were evaluated in a 3-electrode configuration. By using tandem, triple and quadruple junction photocathodes, the onset potentials can be tuned between 1.3 V and 2.5 V vs. RHE. We demonstrate, that the high excess-voltage allows for the substitution of precious metal catalysts, like platinum, by more abundant materials, like nickel, without impairing the device performance. The ability to provide self-contained solar water splitting over a prolonged period of time is demonstrated in a 2-electrode configuration with an impressive solar-to-hydrogen efficiency of 8.6 %.Modeling the current-voltage characteristics of the water splitting device shows good agreement with experimental results and allows for an analysis of the relevant system losses.
%B EMRS Spring Conference
%C 11 May 2015 - 15 May 2015, Lille (France)
Y2 11 May 2015 - 15 May 2015
M2 Lille, France
%F PUB:(DE-HGF)6
%9 Conference Presentation
%U https://juser.fz-juelich.de/record/200800