Regensburg 2016 – scientific programme
O 72.10: Poster
Wednesday, March 9, 2016, 18:15–20:30, Poster A
Experimental Approach for Determining Semiconductor/liquid Junction Energetics by Operando Ambient-Pressure X-ray Photoelectron Spectroscopy — •Matthias H. Richter1,2,7, Michael F. Lichterman1,2, Shu Hu1,2, Ethan J. Crumlin3, Stephanus Axnanda3, Marco Favaro3,4, Walter Drisdell3,4, Zahid Hussain3, Bruce S. Brunschwig1, Zhi Liu3,5,6, Nathan S. Lewis1,2, and Hans-Joachim Lewerenz1,2 — 1Caltech, Pasadena, USA. — 2JCAP, Pasadena, USA. — 3LBNL, Berkeley, USA. — 4JCAP, Berkeley, USA. — 5Chinese Academy of Sciences, China. — 6ShanghaiTech University, China. — 7BTU C-S, Cottbus, Germany.
The performance of a photoelectrochemical solar cell depends strongly on the electrochemical nature of the semiconductor/electrolyte junction . Operando Ambient Pressure X-ray photoelectron spectroscopy investigation of semiconductor/liquid junctions provides quantitative understanding of the energy bands in these photoelectrochemical solar cells [2, 3, 4]. We demonstrate how OAP-XPS may be used to determine these relationships for semiconductor/liquid systems. The data can be analyzed to determine the energy relationship between the electronic energy bands in the semiconductor electrode and the redox levels in the solution. The major conditions for semiconductor-electrolyte contacts including accumulation, depletion, and Fermi-level pinning are observed, and the so-called flat-band energy can be determined.  Science 344 (2014) 1005;  Sci Rep 5 (2015) 9788;  Ener & Env Sci 8 (2015) 2409;  J Electrochem Soc 162 (2016) H1