Synthesis of a Composite Material Consisting of PEDOT:PSS and Solvo-Thermally Synthesized MoS ₂ with a Predominant 1T Phase for the Application in Dye-Sensitized Solar Cells

Due to its unique electronic and structural properties, molybdenum disulfide (MoS 2 ) attracts much attention as a promising material for electrochemical applications. This work aims to synthesize semiconducting 2H-MoS 2 and its conversion to the metallic 1T phase via solvothermal agitation using the dimethylformamide (DMF) solvent. By utilizing the conversion process, we obtained 64.70% 1T phase MoS 2 in the mixed phase of MoS 2 . Phase conversion is confirmed through X-rays diffraction, Raman, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and high-resolution transmission electron microscopy. To prepare the counter electrode of the composite blend, a small portion (1, 3, 10, and 15 wt·%) of 1T/2H MoS 2 is added to poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS) and coated by drop casting on fluorine-doped tin oxide conducting glass. The electrocatalytic properties of all composite counter electrodes are examined through cyclic voltammetry, Tafel polarization, and electrochemical impedance spectroscopy. The 10% MoS 2 /PEDOT:PSS composite shows excellent electrocatalyst properties. The photovoltaic properties of dye-sensitized solar cells (DSSCs) with MoS 2 /PEDOT:PSS composite counter electrodes are analyzed by observing current density–voltage (J–V) curves. The 10% MoS 2 /PEDOT:PSS composite-based DSSC showed the highest power conversion efficiency of 4.74% compared to other composite CEs, and it is comparable to the platinum (Pt) counter electrode-based DSSC. Moreover, the counter electrodes with composites are cost-effective compared to the Pt electrode.