Room Temperature Micro-Photoluminescence Studies of Colloidal WS₂ Nanosheets

Wet-chemical syntheses of quasi two-dimensional (2D) transition metal dichalcogenides (TMDs) have emerged as promising methods for straightforward solution-processing these materials. However, the photoluminescence (PL) properties colloidal TMDs are virtually unexplored due to typically nonemitting synthesis products. In this work, we demonstrate room temperature micro-PL delicate ultrathin WS2 nanosheets synthesized from WCl6 and elemental sulfur in oleic acid oleylamine at 320 °C first time. Both mono- multilayer PL observed, revealing comparable characteristics exfoliated TMD monolayers underpinning high quality nanosheets. addition, long-term air stability is found, control photodegradation structures under laser excitation identified a challenge further advancing nanosheet monolayers. Our results render easily highly 2D semiconductors with optical fully competitive conventionally fabricated TMDs.