CO₂‐Assisted Solution‐Phase Selective Assembly of 2D WS₂‐WO₃⋅H₂O and 1T‐2H MoS₂ to Desirable Complex Heterostructures

Abstract Precise control of the lateral and vertical integration of two‐dimensional (2D) heterostructures is exciting for novel electronic and photovoltaic applications. Fabricating assemblies of high‐quality heterostructures with desirable compositions and sequences is challenging. In this work, with the assistance of supercritical CO₂ (SC CO₂), we successfully prepared the complex heterostructures of WS₂‐WO₃⋅H₂O/1T‐2H MoS₂ with selective stacking assembly. Thanks to the unique properties of SC CO₂, which can help to construct a unique solvent system where the hydrophilic or hydrophobic structure for the 2D layer heterostructure can be chosen, 2H‐WS₂/2H‐MoS₂ assemblies are formed efficiently as the preferred van der Waals heterojunctions. A superior photoelectrochemical activity toward hydrogen evolution based on such the quaternary heterostructures is achieved due to their strong interlayer electronic coupling as well as the increased conductivity and active sites in the heterostructures.