Super-resolved optical mapping of reactive sulfur-vacancy in 2D transition metal dichalcogenides

TL;DR

This paper introduces a high-resolution optical mapping technique for detecting sulfur-vacancy defects in 2D transition metal dichalcogenides, enabling detailed spatial analysis of defects with nanometer precision.

Contribution

The authors develop a novel fluorescence-based localization microscopy method for large-area, high-resolution mapping of sulfur vacancies in 2D TMDs, surpassing previous resolution and throughput limitations.

Findings

Achieved 15 nm localization precision for sulfur vacancies.

Enabled visualization of large structural defects like grain boundaries.

Provided a fast, scalable method for defect mapping in 2D materials.

Abstract

Transition metal dichalcogenides (TMDs) represent an entire new class of semiconducting 2D materials with exciting properties. Defects in 2D TMDs can crucially affect their physical and chemical properties. However, characterization of the presence and spatial distribution of defects is limited either in throughput or in resolution. Here, we demonstrate large area mapping of reactive sulfur-deficient defects in 2D-TMDs coupling single-molecule localization microscopy with fluorescence labeling using thiol chemistry. Our method, reminiscent of PAINT strategies, relies on the specific binding by reversible physisorption of fluorescent probes to sulfur-vacancies via a thiol group and their intermittent emission to apply localization of the labeled defects with a precision down to 15 nm. Tuning the distance between the fluorophore and the docking thiol site allows us to control F\"oster Resonance Energy Transfer (FRET) process and reveal large structural defects such as grain boundaries and line defects, due to the local irregular lattice structure. Our methodology provides a simple and fast alternative for large-scale mapping of non-radiative defects in 2D materials and paves the way for in-situ and spatially resolved monitoring of the interaction between chemical agent and the defects in 2D materials that has general implications for defect engineering in aqueous condition.