Long-Lived Interlayer Excitons in WS₂/Ruddlesden-Popper Perovskite van der Waals Heterostructures

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) transition metal dichalcogenides (TMDs) and perovskites are promising for optoelectronics but have limitations.
• Combining these materials into heterostructures can unlock novel optical properties and overcome individual material drawbacks.

Purpose of the Study:

• To create and investigate a van der Waals (vdW) heterostructure combining monolayer tungsten disulfide (WS₂) and a Ruddlesden-Popper (RP) perovskite, (TEA)₂PbI₄.
• To explore the charge carrier dynamics within this novel WS₂/(TEA)₂PbI₄ heterostructure.

Main Methods:

• Fabrication of a van der Waals heterostructure using monolayer WS₂ and (TEA)₂PbI₄.
• Employing ultrafast transient absorption (TA) spectroscopy to probe charge carrier dynamics.

Main Results:

• Demonstration of a type-II band alignment within the WS₂/(TEA)₂PbI₄ heterostructure.
• Observation of rapid hole transfer from WS₂ to the perovskite layer within 260 femtoseconds (fs).
• Formation of long-lived interlayer excitons (IXs) with a lifetime of 728 picoseconds (ps).

Conclusions:

• The WS₂/(TEA)₂PbI₄ heterostructure exhibits efficient charge transfer and long-lived interlayer excitons.
• This synergistic combination offers a pathway for developing advanced hybrid systems for high-performance optoelectronic devices.