Preparation of MoS2/graphene nanocomposite-based photoanode for dye-sensitized solar cells (DSSCs)

We reported on the preparation of different composition of molybdenum sulfide (MoS2)/graphene nanocomposites by facile hydrothermal route and its further application in the dye-sensitized solar cells (DSSCs). The structural, morphological, optical and textural properties of the samples were systematically investigated by X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Raman, UV-Vis diffuse reflectance spectra (DRS), Photoluminescence and N-2 adsorption-desorption analysis, respectively. XRD and TEM results suggest that hexagonal crystalline structure with uniform spherical shaped nanoparticles are uniformly wrapped on the graphene nanosheets. The incorporated graphene could effectively reducing the band gap (2.38-1.92 eV) and recombination of electron-hole pair. The fabricated DSSCs shows outstanding photo-conversion efficiency (PCE) of 8.92% for MoS2/graphene, which is higher than that of bare MoS2 (3.36%). The enhancement is assigned to less recombination of photo-generated electrons and higher incident photon to current conversion yield as a result of rapid charge collection and higher dye sensitization. Moreover, the synergic effect between the MoS2 and graphene could provide large active path owing to their huge surface area (89.25 m(2)/g) and porous nature (12.23 nm). The mechanism improved by graphene was also explained based on the obtained results.