Enriched Fluorescence Emission from WS₂ Monoflake Empowered by Au Nanoexplorers

Gold nanoparticles (Au NPs) are deposited on monolayer 2D tungsten disulfide (WS₂) microflake (monoflake) to probe the effects of gold deposition on the physical and chemical properties of the WS₂ transition metal dichalcogenides. It is found that the Au NPs behave like nanoexplorers that map out subtle and hidden chemical heterogeneity within the WS₂ monoflake by way of site‐selective decoration on the WS₂ monoflake. The resultant decorated Au NPs patterns trace the concentric fluorescence pattern found on the WS₂ monoflake. The Au NPs enhance the fluorescence intensity in selected regions within the WS₂ monoflake and even activate fluorescence emission from previously dark regions. Most remarkably, the photoluminescence spectra from WS₂ with Au NPs are sharpened and dominated by neutral excitons. This is in stark contrast to photoluminescence emission from pristine WS₂ monoflake where the spectrum exhibits a multitude of emissions from trions, biexcitons, neutral excitons, and defect‐bounded excitons.