CuNi2S4-reduced graphene oxide composites as an efficient counter electrode for high performance dye-sensitized solar cells

• Published in: Journal of materials science. Materials in electronics Vol. 33; no. 24; pp. 19642 - 19655
• Main Authors: Ramki, D., Dharmendira Kumar, M., Siva Karthik, P.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2022; Springer Nature B.V
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Diffusion rate; Dye-sensitized solar cells; Dyes; Electrodes; Energy harvesting; Graphene; Ion diffusion; Materials Science; Nanocomposites; Nanotubes; Optical and Electronic Materials; Photovoltaic cells; Sheets; Solar energy; Structural analysis; Structural hierarchy; Thermal stability; Thin films
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-022-08800-x

Dye-sensitized solar cell (DSSC) technology could become a low-cost solution for solar energy harvesting if the use of expensive dyes and Pt can be avoided. This work reports the development of novel nanohybrid thin films based on CoNi 2 S 4 nanotubes embedded on sheets of reduced graphene oxide (rGO), which can serve as an excellent counter electrode for DSSC showing great promise to replace Pt. The structural and morphological characterization of the nanocomposite films synthesized using a simple one-step hydrothermal method revealed well-defined crystalline nanotubes of CuNi 2 S 4 (with length 200 nm and diameter 10.41 nm) uniformly embedded on the surfaces of the rGO sheets (~ 2.65 μm in size). The optimized CuNi 2 S 4 /rGO nanohybrid film when used as counter electrode in DSSC, photo conversion efficiency as high as 9.68 ± 0.02% was recorded, a value almost equal to that obtained from the DSSC fabricated with Pt as counter electrode (7.01 ± 0.01%) and much higher than that with bare CuNi 2 S 4 (5.01 ± 0.01%) justifying its potential use in Pt-free DSSC. The improved performance of the electrode have been attributed to the hierarchical nanohybrid structure consisting of 1D CuNi 2 S 4 nanotubes embedded on electrically conducting 2D rGO sheets that provides fast ion diffusion pathways, large accessible surface area and good chemical and thermal stability.