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Jens Uhlig. Portrait.

Jens Uhlig

Senior lecturer

Jens Uhlig. Portrait.

More than protection : The function of TiO2interlayers in hematite functionalized Si photoanodes

Author

  • Anurag Kawde
  • Alagappan Annamalai
  • Anita Sellstedt
  • Jens Uhlig
  • Thomas Wågberg
  • Pieter Glatzel
  • Johannes Messinger

Summary, in English

Worldwide significant efforts are ongoing to develop devices that store solar energy as fuels. In one such approach, solar energy is absorbed by semiconductors and utilized directly by catalysts at their surfaces to split water into H2 and O2. To protect the semiconductors in these photo-electrochemical cells (PEC) from corrosion, frequently thin TiO2 interlayers are applied. Employing a well-performing photoanode comprised of 1-D n-Si microwires (MWs) covered with a mesoporous (mp) TiO2 interlayer fabricated by solution processing and functionalized with α-Fe2O3 nanorods, we studied here the function of this TiO2 interlayer by high-energy resolution fluorescence detected X-ray absorption near edge structure (HERFD-XANES) spectroscopy, along with X-ray emission spectroscopy (XES) and standard characterization techniques. Our data reveal that the TiO2 interlayer not only protects the n-Si MW surface from corrosion, but that it also acts as a template for the hydrothermal growth of α-Fe2O3 nanorods and improves the photocatalytic efficiency. We show that the latter effect correlates with the presence of stable oxygen vacancies at the interface between mp-TiO2 and α-Fe2O3, which act as electron traps and thereby substantially reduce the charge recombination rate at the hematite surface.

Department/s

  • LINXS - Institute of advanced Neutron and X-ray Science
  • NanoLund: Centre for Nanoscience
  • Chemical Physics

Publishing year

2020

Language

English

Pages

28459-28467

Publication/Series

Physical Chemistry Chemical Physics

Volume

22

Issue

48

Document type

Journal article

Publisher

Royal Society of Chemistry

Topic

  • Physical Chemistry (including Surface- and Colloid Chemistry)
  • Condensed Matter Physics (including Material Physics, Nano Physics)

Status

Published

ISBN/ISSN/Other

  • ISSN: 1463-9076