Direct Solution-Phase Synthesis and Functionalization of 2D WSe₂ for Ambient Stability

2H phase tungsten diselenide (WSe₂ ) is a p-type 2D semiconductor from the transition metal dichalcogenides (TMDs) family with unique optoelectrical properties. Solution phase production of atomically thin WSe₂ is challenging due to its instability under ambient conditions. We present a highly efficient and scalable solution method for simultaneously exfoliating and functionalizing WSe₂ by leveraging the non-covalent interaction between mercapto-group and bulk WSe₂ . Single and few-layer 2H phase pure WSe₂ sheets of lateral size up to 5 μm with minimal basal plane defects, as revealed by XPS, Raman and FTIR spectroscopy, are produced in a water-ethanol mixture. Remarkably, WSe₂ dispersion remains stable even at high concentrations (10 mg/mL) and exhibited high colloidal stability with a shelf-life exceeding a year. The findings from our study suggest that through precise manipulation of intercalation chemistry, mass production of solution-processable phase-sensitive 2D materials such as WSe₂ can be achieved. This advancement holds great potential for facilitating their practical utilization in various real-world applications.