Charge transfer dynamics and interlayer exciton formation in MoS₂/VOPc mixed dimensional heterojunction

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Mixed-dimensional van der Waals heterojunctions combine materials of different dimensionalities (e.g., 2D MoS2 and 0D VOPc).
• These interfaces exhibit unique properties distinct from their individual components.

Purpose of the Study:

• To investigate photoinduced charge transfer and interlayer exciton formation in a MoS2/VOPc heterojunction.
• To understand the dynamics of charge separation and exciton generation at the interface.

Main Methods:

• Femtosecond transient absorption spectroscopy was employed.
• Selective photoexcitation of MoS2 and VOPc layers was performed.

Main Results:

• Hole transfer from MoS2 to VOPc occurred in ~710 fs upon MoS2 excitation.
• Electron transfer from excited VOPc to MoS2 conduction band was observed in <100 fs.
• Interlayer excitons formed, leading to charge-separated states lasting up to 2.5 ns.

Conclusions:

• Ultrafast charge transfer and long-lived interlayer excitons were demonstrated in the MoS2/VOPc heterojunction.
• These findings highlight the potential for efficient charge separation and exciton formation.
• The observed properties are promising for applications in photovoltaics and optoelectronics.