Carbonaceous-MoS₂ nanoflower-based counter electrodes for bifacial dye-sensitized solar cells

MoS₂-based transition metal dichalcogenide nanoflowers are synthesized using the hydrothermal method and their potential as a counter electrode in dye-sensitized solar cells (DSSCs) is examined. Structural analysis of synthesized MoS₂ is analysed using x-ray diffraction spectra and Raman spectroscopy. The morphology and microstructural properties are investigated using field-emission scanning electron microscopy and high-resolution transmission electron microscopy, respectively. DSSCs are fabricated using different counter electrodes (MoS₂, MoS₂-carbon black and MoS₂-high conductive carbon paste (HCP)), which are deposited using a simple spin-coating method and annealed at a temperature of 80 °C. The electrochemical properties of the fabricated counter electrodes are studied using electrochemical impedance spectroscopy. Among the different counter electrodes, MoS₂–HCP shows better electrochemical performance. The high electrocatalytic and conducting nature of the MoS₂–HCP-based counter electrode produces 5% power conversion efficiency, which is comparable to expensive Pt-based counter electrodes (5.4%). To demonstrate the bifacial concept of DSSC, 2.2% power conversion efficiency is attained with rear-side illumination under one sun (100 mW cm⁻², AM 1.5 G). (paper)