In-Plane Field Enabled Dissociation Dynamics of Defect-Bound Excitons and Excitonic Oscillator Strength Redistribution in Monolayer WS₂

Monolayer transition metal dichalcogenides (TMDs) host strongly bound many-particle excitonic complexes, providing a rich platform to develop insights into the intriguing questions related to many-body physics and light–matter interactions in quantum-confined 2D semiconductors. This work explores monolayer WS 2, demonstrating how an in-plane electric field can dynamically redistribute oscillator strength among various excitonic states─from trions, charged biexcitons, and defect-bound (localized) excitons to neutral excitons. This field-induced redistribution unveils complex exciton-defect interactions and coupling mechanisms, elucidating their role in modulating many-body interactions and tuning the optoelectronic properties of the material. The observations contribute to understanding light–matter interactions in quantum-confined systems, with relevance to future tunable photonic devices and quantum information technology applications.