This report describes the synthesis of a layered molybdenum disulfide (MoS2)–tungsten disulfide (WS2) heterostructure onto fluorine doped tin oxide covered glass substrates using a combination of chemical bath deposition and RF sputtering techniques. FESEM images revealed that the MoS2–WS2 heterostructure surface consisted of a cauliflower structured array of grains with spherical structures. The vertically aligned atomic layers were explored by transmission electron microscopy images for MoS2–WS2 heterostructure. Hydrogen evolution reaction (HER) kinetics show overpotentials of 151 and 175 mV @ 10 mA/cm2 with Tafel slope values of 90 and 117 mV/decade for pristine MoS2 and WS2 electrocatalysts, respectively. Improved electrocatalytic activity for HER was established with overpotential 129 mV @ 10 mA/cm2 and Tafel slope 72 mV/decade for the MoS2–WS2 heterostructure. The MoS2–WS2 heterostructure electrocatalyst showed robust continuous HER performance over 20 h in an acidic solution. This improved electrochemical performance emerges from the elevation of electron–hole separation at the layer interfaces and sharing of active edge sites through the interface. This study provides the basis to develop new applications for transition-metal dichalcogenides heterostructures in future energy conversion systems.

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Molybdenum disulfide (MoS) has recently emerged as a promising candidate for fabricating ultrathin-film photovoltaic devices. These devices exhibit excellent photovoltaic performance, superior flexibility, and low production cost. Layered MoS deposited on p-Si establishes a built-in electric field at MoS/Si interface that helps in photogenerated carrier separation for photovoltaic operation. We propose an AlO-based passivation at the MoS surface to improve the photovoltaic performance of bulklike MoS/Si solar cells. Interestingly, it was observed that AlO passivation enhances the built-in field by reduction of interface trap density at surface. Our device exhibits an improved power conversion efficiency (PCE) of 5.6%, which to our knowledge is the highest efficiency among all bulklike MoS-based photovoltaic cells. The demonstrated results hold the promise for integration of bulklike MoS films with Si-based electronics to develop highly efficient photovoltaic cells.

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