Time-Resolved Observations of Photo-Generated Charge-Carrier Dynamics in Sb2Se3 Photocathodes for Photoelectrochemical Water Splitting

Wooseok Yang, Seungmin Lee, Hyeok Chan Kwon, Jeiwan Tan, Hyungsoo Lee, Jaemin Park, Yunjung Oh, Hyunyong Choi, Jooho Moon

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)

Abstract

Solar-energy conversion by photoelectrochemical (PEC) devices is driven by the separation and transfer of photogenerated charge carriers. Thus, understanding carrier dynamics in a PEC device is essential to realizing efficient solar-energy conversion. Here, we investigate time-resolved carrier dynamics in emerging low-cost Sb2Se3 nanostructure photocathodes for PEC water splitting. Using terahertz spectroscopy, we observed an initial mobility loss within tens of picoseconds due to carrier localization and attributed the origin of carrier localization to the rich surface of Sb2Se3 nanostructures. In addition, a possible recombination at the interface between Sb2Se3 and the back contact is elucidated by time-resolved photoluminescence analysis. We also demonstrated the dual role of the RuOx co-catalyst in reducing surface recombination and enhancing charge transfer in full devices using intensity-modulated spectroscopy. The relatively low onset potential of the Sb2Se3 photocathode is attributed to the sluggish charge transfer at a low applied bias rather than to fast surface recombination. We believe that our insights on carrier dynamics would be an important step toward achieving highly efficient Sb2Se3 photocathodes.

Original languageEnglish
Pages (from-to)11088-11097
Number of pages10
JournalACS Nano
Volume12
Issue number11
DOIs
Publication statusPublished - 2018 Nov 27

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Government of Korea (MSIP) (2012R1A3A2026417). S.L. and H.C. were supported by the National Research Foundation of Korea (NRF) through the Government of Korea (MSIP) (grant nos. NRF-2015R1A2A1A10052520).

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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