Hot-Carrier Transfer at Photocatalytic Silicon/Platinum Interfaces: Article No. 144705

Chongjian Zhang, Yunyan Fan, Xiaochun Huang, Kelvin Zhang, Matthew Beard, Ye Yang

Research output: Contribution to journalArticlepeer-review

10 Scopus Citations

Abstract

Interfacial charge transfer from silicon to heterogeneous catalysts plays a key role in silicon-based photoelectrochemical systems. In general, prior to interfacial charge transfer, carriers that are generated by photons with energies above the bandgap dissipate the excess kinetic energy via hot-carrier cooling, and such energy loss limits the maximum power conversion efficiency. The excess energy of hot-carriers, however, could be utilized through hot-carrier transfer from silicon to the catalysts, but such hot-carrier extraction has not yet been demonstrated. Here, we exploit transient reflection spectroscopy to interrogate charge transfer at the interface between silicon and platinum. Quantitative modeling of the surface carrier kinetics indicates that the velocity of charge transfer from silicon to platinum exceeds 2.6 x 107 cm s-1, corresponding to an average carrier temperature of extracted carriers of ~600 K, two times higher than the lattice temperature. The charge transfer velocity can be controllably reduced by inserting silica spacing layers between silicon and platinum.
Original languageAmerican English
Number of pages6
JournalThe Journal of Chemical Physics
Volume152
Issue number14
DOIs
StatePublished - 2020

NREL Publication Number

  • NREL/JA-5900-74064

Keywords

  • interfacial carrier dynamics
  • interfacial spectroscopy
  • Si interfaces
  • solar-photochemistry

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