Ultrafast Charge Transfer Cascade in a Mixed-Dimensionality Nanoscale Trilayer

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Abstract

Innovation in optoelectronic semiconductor devices is driven by a fundamental understanding of how to move charges and/or excitons (electron-hole pairs) in specified directions for doing useful work, e.g., for making fuels or electricity. The diverse and tunable electronic and optical properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs) and one-dimensional (1D) semiconducting single-walled carbon nanotubes (s-SWCNTs) make them good quantum confined model systems for fundamental studies of charge and exciton transfer across heterointerfaces. Here we demonstrate a mixed-dimensionality 2D/1D/2D MoS2/SWCNT/WSe2 heterotrilayer that enables ultrafast photoinduced exciton dissociation, followed by charge diffusion and slow recombination. Importantly, the heterotrilayer serves to double charge carrier yield relative to a MoS2/SWCNT heterobilayer and also demonstrates the ability of the separated charges to overcome interlayer exciton binding energies to diffuse from one TMDC/SWCNT interface to the other 2D/1D interface, resulting in Coulombically unbound charges. Interestingly, the heterotrilayer also appears to enable efficient hole transfer from SWCNTs to WSe2, which is not observed in the identically prepared WSe2/SWCNT heterobilayer, suggesting that increasing the complexity of nanoscale trilayers may modify dynamic pathways. Our work suggests "mixed-dimensionality" TMDC/SWCNT based heterotrilayers as both interesting model systems for mechanistic studies of carrier dynamics at nanoscale heterointerfaces and for potential applications in advanced optoelectronic systems.
Original languageAmerican English
Pages (from-to)8190-8198
Number of pages9
JournalACS Nano
Volume18
Issue number11
DOIs
StatePublished - 2024

NREL Publication Number

  • NREL/JA-5K00-88449

Keywords

  • carbon nanotubes
  • charge transfer
  • excitons
  • heterojunctions
  • monolayer semiconductors
  • photoinduced charge transfer
  • photovoltaics
  • solar-photochemistry
  • transition metal dichalcogenides

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