WS₂/MoS₂ Heterostructures through Thermal Treatment of MoS₂ Layers Electrostatically Functionalized with W₃S₄ Molecular Clusters

Abstract

The preparation of 2D stacked layers combining flakes of different nature gives rise to countless numbers of heterostructures where new band alignments, defined at the interfaces, control the electronic properties of the system. Among the large family of 2D/2D heterostructures, the one formed by the combination of the most common semiconducting transition metal dichalcogenides, WS 2 /MoS 2 ,h as awakened great interest owing to its photovoltaic and photoelectrochemical properties.S olution as well as dry physical methods have been developedt oo ptimizet he synthesis of these heterostructures. Here, as uspension of negatively chargedM oS 2 flakes is mixed with am ethanolic solution of ac ationic W 3 S 4 -core cluster,g iving rise to ah omogeneous distribution of the clusters over the layers.I nasecond step, ac alcination of this molecular/2D heterostructure under N 2 leads to the formation of cleanW S 2 /MoS 2 heterostructures, where the photoluminescence of both counterparts is quenched, proving an efficient interlayer coupling. Thus,t his chemicalm ethod combines the advantages of as olution approach (simple, scalable, and low-cost) with the good quality interfaces reached by using more complicated traditional physicalmethods.[a] M. Morant-Giner,I.B rotons-Alcµzar, Dr.A.A lberola,D r. S. Tatay, Scheme1.Pictorial representationo fW S 2 /MoS 2 synthesis:( i) synthesiso fcluster@MoS 2 ;(ii)calcination of cluster@MoS 2 to give rise to the final heterostructure formed by MoS 2 layersi nb etween WS 2 flakes( WS 2 /MoS 2 ).