Ultrafast Charge Transfer Cascade in a Mixed-Dimensionality Nanoscale Trilayer

Area of Science:

• Materials Science
• Nanotechnology
• Optoelectronics

Background:

• Optoelectronic device innovation relies on controlling charge and exciton movement.
• Two-dimensional (2D) transition metal dichalcogenides (TMDCs) and one-dimensional (1D) single-walled carbon nanotubes (s-SWCNTs) are key quantum-confined systems.
• Studying charge and exciton transfer across heterointerfaces is crucial for device performance.

Purpose of the Study:

• To demonstrate a mixed-dimensionality 2D/1D/2D heterotrilayer for ultrafast photoinduced exciton dissociation.
• To investigate charge diffusion and recombination dynamics at nanoscale heterointerfaces.
• To explore potential applications in advanced optoelectronic systems.

Main Methods:

• Fabrication of a MoS₂/SWCNT/WSe₂ heterotrilayer.
• Investigation of photoinduced exciton dissociation and charge carrier dynamics.
• Comparison of heterotrilayer performance with heterobilayer systems.

Main Results:

• The heterotrilayer achieved ultrafast exciton dissociation, followed by charge diffusion and slow recombination.
• Charge carrier yield was doubled compared to a MoS₂/SWCNT heterobilayer.
• Separated charges overcame interlayer exciton binding energies, leading to unbound charges.
• Efficient hole transfer from SWCNTs to WSe₂ was observed, a phenomenon not seen in heterobilayers.

Conclusions:

• Mixed-dimensionality TMDC/SWCNT heterotrilayers are promising for mechanistic studies of carrier dynamics.
• These heterotrilayers offer potential for advanced optoelectronic applications.
• Increasing nanoscale trilayer complexity can modify dynamic pathways for charge transfer.