Synthesis and characterisation of nickel cobalt sulfide nanoparticles by the solvothermal method for dye-sensitized solar cell applications

The aims of this study were to synthesize and characterize a nickel cobalt sulfide (NiCo2S4), namely a ternary transition metal sulfide, by the solvothermal method for DSSC applications. Four samples of NiCo2S4 nanoparticles (NCS1, NCS2, NCS3 and NCS4) were synthesized by varying the amount of thiourea used in the synthesis. The samples were found to have an average crystallite size of 3 nm. The FE-SEM images of the samples show the particles to have uniform spherical shape, with agglomeration into clusters in some places. The presence of Co, Ni and S was confirmed through EDS analysis. From the fingerprint region of the FTIR spectra, the presence of sulfur was confirmed. A peak at 672 cm(-1) was observed in the Raman spectra which matches the reported value of 678 cm(-1), confirming the formation of NiCo2S4 nanoparticles. The efficiencies of the DSSCs fabricated with NCS2, NCS3 and NCS4 were found to be 0.87, 1.54 and 1.87%. From the results it is concluded that NiCo2S4 can be a candidate for use as a counter electrode in DSSC applications. (C) 2019 Elsevier Ltd. All rights reserved.