Interface-Tailored Secondary Excitation and Ultrafast Charge/Energy Transfer in Ti₃C₂T-MoS₂ Heterostructure Films

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Efficient charge/energy separation in plasmonic materials is key for photochemical and optoelectronic applications.
• Understanding carrier dynamics in plasmonic-semiconducting heterostructures like MXene-TMDs is crucial but remains challenging.

Purpose of the Study:

• To investigate the mechanisms of plasmon-induced carrier dynamics at Ti3C2Tx-MoS2 interfaces.
• To explore secondary excitation and ultrafast charge/energy transfer phenomena.
• To engineer interfacial thermal transport for enhanced performance.

Main Methods:

• Fabrication of large-scale Ti3C2Tx and MoS2 films via self-assembly techniques.
• Assembly of macroscopic heterostructures with controlled interface sequences.
• Utilized transient absorption and optical pump-terahertz probe spectroscopy.

Main Results:

• Observed a secondary excitation in MoS2 driven by Ti3C2Tx surface plasmon resonance (∼70 ps rise time).
• Demonstrated interfacial thermal transport engineering to extend this time to ∼175 ps.
• Identified sub-150 fs ultrafast charge/energy transfer from Ti3C2Tx to MoS2, boosting MoS2 photoconductivity by up to 180%.

Conclusions:

• Uncovered novel secondary excitation and ultrafast charge transfer mechanisms in Ti3C2Tx-MoS2 heterostructures.
• Highlighted the role of interfacial engineering in manipulating excited-state dynamics.
• Provided critical insights for developing high-performance plasmonic MXene-based heterostructures for advanced applications.