Influence of [Cu]/[Cu+Sn] molar ratios in p-type Cu–Sn–S photoelectrodes on their photoelectrochemical performances in water and salt–water solutions

Kong Wei Cheng*

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

4 Scopus citations

Abstract

Ternary p-type copper–tin–sulfide photoelectrodes are prepared on various substrates by using the sulfurization of co-sputtered Cu–Sn metal precursors. The influence of the [Cu]/[Cu+Sn] molar ratios in samples on structural and photoelectrochemical performances of samples in various electrolytes is examined. X-ray diffraction patterns of samples after the sulfurization process show that the samples change from the cubic Cu2SnS3 phase, the cubic Cu2SnS3/orthorhombic Cu4SnS4 mixing phases to the orthorhombic Cu4SnS4 phase with an increase in the [Cu]/[Cu+Sn] molar ratio in metal precursors. The phase transition from the cubic Cu2SnS3 to the orthorhombic Cu4SnS4 phase is observed at the [Cu]/[Cu+Sn] molar ratio in the range of 0.72–0.73 in metal alloys. Direct energy band gaps of the samples are in the range of 0.96–1.22 eV. All samples are the p-type semiconductors with the carrier concentration and mobility in the ranges of 8.79 × 1018–3.57 × 1020 cm−3 and 2.22–0.27 cm2/V s, respectively, depending on the [Cu]/[Cu+Sn] molar ratio in samples. The maximum photoelectrochemical performances of the samples in 0.5 M K2SO4 and 1 M NaCl aqueous solutions are 0.55 and 0.34 mA/cm2 at an external potential of −1.2 V versus an Ag/AgCl reference electrode under light illumination with the light intensity of 100 mW/cm2, respectively.

Original languageEnglish
Pages (from-to)209-219
Number of pages11
JournalJournal of the Taiwan Institute of Chemical Engineers
Volume75
DOIs
StatePublished - 06 2017

Bibliographical note

Publisher Copyright:
© 2017 Taiwan Institute of Chemical Engineers

Keywords

  • Photoelectrode
  • Salt–water splitting
  • Sputtering
  • Ternary metal sulfide

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