Photoelectrochemical Characterisation on Surface-Inverted Black Silicon Photocathodes by Using Platinum/Palladium Co-catalysts for Solar-to-Hydrogen Conversion

Ahmed Farid Halima, Xinyi Zhang, Douglas Robert MacFarlane

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4 Citations (Scopus)

Abstract

Black silicon (bSi) has recently captured research attention in photoelectrochemical (PEC) solar-to-hydrogen (STH) conversion devices. Because nanostructuring of silicon retains the photovoltaic attributes of the material, it also provides a range of excellent physicochemical properties, such as a vast active-site-rich electrochemical interface, owing to a high aspect ratio, and important light-scattering attributes, which significantly improve photoconversion. One method to gain control over p-type bSi interface energetics is surface inversion of the p-type interface by phosphorus doping to introduce a shallow n+-emitter layer, which provides a thin p–n junction at the interface of the nanostructures. Although this concept has been suggested in the literature, it has not been demonstrated experimentally for a platinum/palladium co-catalysed bSi photocathode device for STH conversion. Herein, preliminary investigations and proof-of-concept studies are reported for the fabrication and PEC characterisation of surface-inverted p-type bSi photocathodes prepared by wet chemical etching. The PEC tests on p-bSi|n+ photocathodes show that, for both metal nanoparticles (Pt and Pd), the catalytic activity for proton conversion is increased; this is evident from an anodic shift in the onset potentials shifts to 0.24 and 0.29 V and an increase in photocurrent by 9 and 13.8 mA cm−2, respectively, at 0 V versus a reversible hydrogen electrode, as a result of introducing the emitter layer.

Original languageEnglish
Pages (from-to)651-657
Number of pages7
JournalChemPlusChem
Volume83
Issue number7
DOIs
Publication statusPublished - 1 Jul 2018

Keywords

  • electrochemistry
  • nanostructures
  • photochemistry
  • silicon
  • surface chemistry

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