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DS: Fachverband Dünne Schichten
DS 4: Atomic Layer Deposition
DS 4.3: Vortrag
Montag, 11. März 2013, 12:45–13:00, H8
An efficient Si photo cathode for a wide range of electrolyte pH values — •Chittaranjan Das1, Massimo Tallarida1, Katarzyna Skorupska2, Hans-Joachim Lewerenz2,3, and Dieter Schmeisser1 — 1Applied physics and sensors,BTU Cottbus, Germany — 2Institute for Solar Fuels and Energy Storage Materials,HZB, Berlin , Germany — 3California Institute of Technology, 1200 East California, Pasadena , USA
Hydrogen fuel cells, being environmental friendly to produce energy, are a technology of future. One of the efficient ways to produce hydrogen is solar driven photocatalysis using semiconducting materials as photo electrodes. The choice of electrodes is a crucial factor and is done on the basis of photo corrosion stability, light absorption efficiency, and photocarrier lifetime. P-type Si can be used as photo cathode to produce H2 by direct photocatalysis. Si cathodes can be used in acidic electrolytes to have efficient photo catalytic activity but they are unstable in alkaline electrolytes. Therefore, to use both Si electrodes in the same electrolyte, their chemical stability should be extended over a wide range of pH. To this purpose we modified the surface of a p-type Si photocathode with very thin films of TiO2 grown by atomic layer deposition (ALD). We found that the modified Si cathode shows an increased photoresponse and a lower onset potential with respect to the pristine surface and an increased stability at various pH values.