Competitive Hole Transfer from CdSe Quantum Dots to Thiol Ligands in CdSe-Cobaloxime Sensitized NiO Films Used as Photocathodes for H2 Evolution

Mohamed Abdellah, Shihuai Zhang, Mei Wang, Leif Hammarström

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Quantum dot (QD) sensitized NiO photocathodes rely on efficient photoinduced hole injection into the NiO valence band. A system of a mesoporous NiO film co-sensitized with CdSe QDs and a molecular proton-reduction catalyst was studied. While successful electron transfer from the excited QDs to the catalyst is observed, most of the photogenerated holes are instead quenched very rapidly (ps) by hole trapping at the surface thiols of the capping agent used as linker molecules. We confirmed our conclusion by first using a thiol free capping agent and second varying the thiol concentration on the QD's surface. The later resulted in faster hole trapping as the thiol concentration increased. We suggest that this hole trapping by the linker limits the H2 yield for this photocathode in a device.

Original languageEnglish
Pages (from-to)2576-2580
Number of pages5
JournalACS Energy Letters
Volume2
Issue number11
DOIs
Publication statusPublished - Nov 10 2017

ASJC Scopus subject areas

  • Chemistry (miscellaneous)
  • Energy Engineering and Power Technology
  • Fuel Technology
  • Renewable Energy, Sustainability and the Environment
  • Materials Chemistry

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