[en] Highlights: • A new structure CZTS-MWCNTs film as composite CE was fabricated via a spin coating process. • A novel DSSC was also constructed with DS-TiO₂ films as the photoanode and CZTS-MWCNTs films as the composite CE. • CZTS NPs were synthesized by a low-cost solvothermal process to high-efficiency solar cells. • The prepared cell achieve efficiency as high as 9.04% which is similar to conventional Pt-based DSSC (8.74%). - Abstract: For the purpose of increasing the power conversion efficiency (PCE) meanwhile decreasing the cost of dye-sensitized solar cell (DSSC), Cu₂ZnSnS₄- multiwall carbon nanotubes (CZTS-MWCNTs) nanohybrid Pt-free counter electrode (CE) was prepared via a facile fabricating route. In brief, CZTS nanoparticles were synthesized by a solvothermal method and the composite film was fabricated by spin coating the aqueous solution of the composite. The short-circuit current density and PCE of the DSSC with CZTS-MWCNTs CE were found to be 16.62 mA cm⁻² and 9.04%, respectively. But the corresponding values were 15.42 mA cm⁻² and 8.74% for a DSSC with a pure Pt-CE. This is owing to the synergistic effect of the intrinsic superior electrocatalytic activity of the CZTS nanoparticles and highly specific surface area and high electrical conductivity of the MWCNTs. The presence and distribution of CZTS-MWCNTs on the CE were characterized by X-Ray Diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM), respectively. Cyclic voltammetry (CV) and electrochemical impedance spectra (EIS) were examined for confirming the high electrocatalytic efficiency of this nanohybrid system.